Difference between revisions of "Stakeholder Needs Definition"

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[[Stakeholder Requirement (glossary)|Stakeholder requirements]] represent the views of [[User (glossary)|users]], [[Acquirer (glossary)|acquirers]], and [[Customer (glossary)|customers]] regarding the problem (or opportunity), through a set of requirements for a solution that can provide the services needed by the [[Stakeholder (glossary)|stakeholders]] in a defined environment. Stakeholder Requirements describe the overall objectives of the system, its principal stakeholders, its context of use, the specific needs which should be satisfied and how success will be assessed.
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'''''Lead Author:''''' ''Tami Katz,'' '''''Contributing Authors:''''' ''Lou Wheatcraft, Mike Ryan''
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''Stakeholder Needs Definition'', the second process in Concept Definition, explores what {{term|Capability (glossary)|capabilities}} are needed by various stakeholders for the {{Term|System-of-Interest (glossary)|system-of-interest}} (SoI) to accomplish the mission. The outcome of the Stakeholder Needs Definition process is used as the basis of [[System Validation]], as well as input into the [[System Requirements Definition]] process.
  
Stakeholder requirements play major roles in the Systems Engineering, they
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Note that the first process, Business or Mission Analysis, is often performed iteratively with Stakeholder Needs Definition to better understand the problem, threat, or opportunity space, as well as options of the solution space. 
*form the basis of [[System Requirement (glossary)|system requirements]] activities;
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==Purpose and Definition==
*form the basis of system [[Validation (glossary)|validation]] and stakeholder acceptance ;
 
*are a reference for [[Integration (glossary)]] and [[Verification (glossary)|verification]] activities; and
 
*a means of communication between the technical staff, management and finance and the stakeholder community.
 
  
This topic provides knowledge about the idea of stakeholder needs and requirements; the activities necessary to elicit and prioritize the needs of the stakeholder(s); and transforming those needs into stakeholder requirements. The definition of the set of stakeholder requirements is the primary outcome of these activities which start in [[Concept Definition]]. The definition of the problem or the issue to be solved and/or the opportunity for developing a new solution or improving a system-of-interest (SoI) must begin prior to starting the activities necessary to define stakeholder needs and requirements. This means that an initial context of use of the new or modified mission, operation, or capability has already been characterized (see the [[Mission Analysis]] topic).  System Requirements are considered in detail during [[System Definition (glossary)]]. None of the above can be considered complete until consistency between the two has been achieved, as demonstrated by Traceability, for which a number of iterations may be needed.  
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{{term|Stakeholder Needs and Requirements (glossary)|Stakeholder needs}} represent a user, acquirer, customer, and other {{term|Stakeholder (glossary)|stakeholders}} perspective of the SoI, which are then transformed into {{term|System Requirement (glossary)|system requirements}} which communicate a developer perspective of the SoI. When stakeholder needs are combined with results of multiple analysis activities that includes risks, drivers, constraints, and life cycle concepts analysis, as shown in Figure 1, the result is an overall integrated set of needs.
  
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[[File:Figure StkhldrNeeds-1 from INCOSE NRM.jpg|thumb|900px|center|'''Figure 1. Establishment of an Integrated Set of Needs ensures that all perspectives are analyzed during the Stakeholder Need Definition process, including risks, drivers, constraints, and life cycle concepts analysis and maturation.''' This figure is reprinted with permission of Lou Wheatcraft and Mike Ryan. All other rights are reserved by the copyright owner.]]
  
==Purpose and Definition==
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The establishment of the integrated set of needs forms the basis of a full understanding of the capabilities expected of the SoI, and these needs are ultimately transformed into a set of design-input requirements on the SoI as part of the [[System Requirements Definition]] process.
The purpose of defining stakeholder requirements is to elicit a set of needs related to a new or changed mission for an enterprise (see [[Mission Analysis]] (MA) for information relevant to identifying and defining the mission or operation), and to transform these needs into clear, concise, and verifiable stakeholder requirements.
 
 
Stakeholder needs analysis is the elicitation, communication, [[Validation (glossary)|validation (glossary)]] and refinement of the needs and objectives of the enterprise or set of stakeholders. Stakeholder needs analysis is aimed at understanding a potential capability (often identified through MA) that is needed to address an identified problem or opportunity. After defining the stakeholder needs and requirements, they interact with the MA to transform the defined set of needs into stakeholder requirements (also known as mission requirements) that reflect these needs.
 
  
 
==Principles and Concepts==
 
==Principles and Concepts==
  
===From the Capture of Needs to the Definition of Stakeholder Requirements===
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The results of the [[Business or Mission Analysis]] is provided as inputs into the Stakeholder Needs Definition process (shown in Figure 2).  This input includes the problem, threat or opportunity statement capturing why the project is worth doing, the mission, goals and objectives (MGOs) and measures of success used as the criteria for assessing project success, along with identification of major stakeholders, initial life cycle concepts, and initial concepts of the solution space (architecture and design).
Several steps are necessary to understand the maturity of stakeholder needs and to understand how to improve upon that maturity. Figure 1 presents the ''cycle of needs'' as it can be deduced from Professor Shoji Shiba's and Professor Noriaki Kano's works and courses, and is adapted here for systems engineering (SE) purposes.
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[[File:Figure StkhldrNeeds-2 SEBoK Original.jpg|thumb|900px|center|'''Figure 2.''' '''Stakeholder Needs Definition expands upon the Business or Mission Analysis results to refine the set of needs for the System of Interest.''' (SEBoK Original)]]
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The Stakeholder Needs Definition process continues the life cycle concepts definition activities to ensure the {{Term|System-of-Interest (glossary)|system-of-interest (SoI)}} provides the capabilities needed by users and other stakeholders in the intended operational environment.  This process is much more than identification and elicitation of need or requirement statements from various stakeholders, it consists of a series of analysis activities done to ensure that all parameters are captured, including risks, drivers, constraints, as well as the SoI life cycle concepts analysis and maturation; this effort results in an integrated set of needs as shown in Figure 3.
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[[File:Figure StkhldrNeeds-3 from INCOSE NRM.jpg|thumb|900px|center|'''Figure 3. Establishment of an integrated set of needs ensures that all perspectives are analyzed during the Stakeholder Need Definition process, including risks, drivers, constraints, and life cycle concepts analysis and maturation.''' This figure is reprinted with permission of Lou Wheatcraft. All other rights are reserved by the copyright owner.]] 
  
[[File:SEBoKv05_KA-SystDef_Cycle_of_needs.png|600px|thumb|center| '''Figure 1. Cycle of Needs (Faisandier 2012).''' Permission granted by Singery'Com. All other rights are reserved by the copyright owner.]]
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The result of this process is a well-formed integrated set of needs that is correct, consistent, complete, and feasible. It is this set of needs that defines the scope of the project which the organization agrees to provide the resources necessary for developing the SoI, and against which the requirements, design, and the realized SoI will be validated against.  
  
Figure 1 shows the steps and the position of the stakeholder requirements and system requirements in the engineering cycleBelow are explanations of each stage of requirements (Faisandier 2012); to illustrate this, an example of a system related to infectious disease identification is provided:  
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=== '''Nomenclature discussion''' ===
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This process is frequently referred to as the "Stakeholder Needs and Requirements" process.  Because various guides, textbooks, and standards refer to stakeholder “expectations, needs, and requirements” as if they are the same, resulting in confusion as to what is an “expectation” versus a “need” and a “requirement”, this article focuses on the process of developing an integrated set of stakeholder needsThe term "stakeholder requirements" is considered a set of requirements on the SoI established by the stakeholder, as transformed from their needs, which are provided as additional input towards the life cycle concepts analysis and maturation activities from which the integrated set of needs is defined. In Figure 3, this is designated as both "stakeholder needs, requirements, and expectations" as well as the "higher-level requirements" inputs.
  
*'''Real needs''' are those that lie behind any perceived needs (see below); they are conditioned by the context in which people live. As an example, a generic need could be the ability to ''identify infectious diseases easily.'' Often, real needs appear to be simple tasks.
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==Process Approach==
*'''Perceived needs''' are based on a person’s awareness that something is wrong, that there is a lack of something, that there is something that could improve a situation, or that there are business, investment, or market opportunities. Perceived needs are often presented as a list of organized expectations resulting from an analysis of the usage conditions for the considered action (see the [[Mission Analysis]] topic). Following from the infectious disease example above, the real need might be perceived as a need to ''carry out medical tests in particular circumstances (laboratories, points of care, hospitals, and/or human dispensaries).'' Since the real need is seldom clearly expressed, richness of the knowledge of the perceived needs is used as a basis for potential solutions. This step has to be as complete as possible to cover all the contexts of use.
 
*'''Expressed needs''' originate from perceived needs in the form of generic actions or constraints, and are typically prioritized. In the example, if safety is the primary concern, the expressed need to ''protect the operator against contamination'' may take priority over other expressed needs such as ''assist in the execution of tests.'' When determining the expressed needs, the analysis of the expected mission or services in terms of operational scenarios takes place.
 
*'''Retained needs''' are selected from the expressed needs. The selection process uses the prioritization of expressed needs to achieve something or make solutions feasible. The retained needs allow the consideration of potential solutions for a SoI. These retained ''stakeholder intentions do not serve as stakeholder requirements, since they often lack definition, analysis, and possibly consistency and feasibility. Using the concept of operations to aid the understanding of the stakeholder intentions at the organizational level and the system operational concept from the system perspective, requirements engineering leads stakeholders from those initial intentions to structured and more formal stakeholder requirement statements'' (ISO/IEC/IEEE 29148 2011). Characteristics of good requirements can be found in ISO/IEC/IEEE 29148 (2011).  Exploration of potential solutions must start from this step. The various solutions suggested at this step are not yet products, but describe means of satisfying the stakeholder requirements. Each potential solution imposes constraints on the potential future SoI.
 
*'''Specified needs''', generally called [[System Requirement (glossary) |system requirements (glossary)]], are the translation of the stakeholder requirements to represent the views of the supplier, keeping in mind the potential, preferred, and feasible solutions.  ''The stakeholder requirements are then transformed into system requirements for the SoI, in accordance with Clauses 5.2.4, 5.2.5, and 5.2.6. Consistent practice has shown this process requires [[Iteration (glossary)|iterative]] and [[Recursion (glossary)|recursive]] steps in parallel with other life cycle processes through the system design hierarchy. The recursive application of the processes in Clause 6 will generate lower-level system element requirements'' (ISO/IEC/IEEE 29148 2011). 
 
*'''Realized needs''' are the product, service or enterprise realized, taking into account every system requirement (and hence, the stakeholder requirement(s)).
 
  
Each class of needs listed above aligns with an area of the SE process.  For example, the development of ''specified needs'' requirements is discussed in the [[System Requirements]] topic.  For more information on how requirements are used in the systems engineering process, please see the [[System Definition]] knowledge area (KA).
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=== Inputs to the Stakeholder Needs Definition Process ===
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The inputs from the Business or Mission Analysis process includes identification of major stakeholders, definition of the problem, threat, or opportunity, elaboration of the MGOs and measures of success, capture of preliminary life cycle concepts, and identification of initial concepts of the solution space (architecture and design).
  
===Identifying Stakeholders and their Requirements===
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=== Activities of the Process ===
Stakeholders of a SoI may vary throughout the [[Life Cycle (glossary)|life cycle]]. Thus, in order to get a complete set of needs and subsequent requirements, it is important to consider all stages of the life cycle when identifying the stakeholders or classes of stakeholders.  
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There are several activities performed during this process:
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* Identify additional stakeholders or classes of stakeholders across the life cycle.
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* Elicit, capture, consolidate and prioritize stakeholder needs, requirements, and expectations.
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* Identify drivers and constraints on the SoI and its development efforts.
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* Identify potential {{Term|Risk (glossary)|risks}} (such as threats and hazards) that could prevent the SoI from successful operation (see [[Risk Management]] for further information on addressing risks).
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* Mature and analyze the life cycle concepts.
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* Identify, baseline, and manage the integrated set of needs.
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The activities behind each of these are described in the following sections.
  
Every system has its own stages of life; these may include concept, development, production, operations, sustainment, and retirement (for more information, please see [[Life Cycle Models]]). For each stage, a list of all stakeholders having an interest in the future system is identified. The goal is to get every stakeholder’s point of view for every stage of the system life in order to consolidate a complete set of stakeholder needs that can be prioritized and transformed into the set of stakeholder requirements as exhaustively as possible.  Examples of stakeholders are provided in Table 1.
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=== Identify Stakeholders ===
  
<center>
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Stakeholders are the primary source of needs and requirements, therefore for the project to be successful, all relevant stakeholders must be identified and included from the beginning of the project. Leaving out a relevant stakeholder often results in missing needs and requirements and a failure to pass system validation.  Stakeholders can include, but are not limited to, customers, sponsors, organization decision makers, regulatory organizations, developing organizations, integrators, testers, users, operators, maintainers, support organizations, the public at large (within the context of the business and proposed solution), and those involved in the disposal or retirement of the SoI.  Stakeholders can be both internal and external to the organization. There can be many stakeholders for a SoI over its life cycle; therefore, considering the {{Term|Life Cycle (glossary)|life cycle}} concepts provides a thorough source for stakeholder identification.  Examples of stakeholders are provided in Table 1.
{|
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{| class="wikitable"
 
|+'''Table 1. Stakeholder Identification Based on Life Cycle Stages.''' (SEBoK Original)
 
|+'''Table 1. Stakeholder Identification Based on Life Cycle Stages.''' (SEBoK Original)
 
!Life Cycle Stage
 
!Life Cycle Stage
 
!Example of Related Stakeholders
 
!Example of Related Stakeholders
 
|-
 
|-
|Engineering
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|Concept
|Acquirer, panel of potential users, marketing division, research and development department, standardization body, suppliers, verification and validation team, production system, regulator/certification authorities, etc.
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|Paying customer, sponsor, project team, project manager, procurement, research and development, suppliers, regulating authorities, public, marketing, end users, operators, compliance office, regulators, owners of enabling systems, owners of external systems, Approving Authorities
 
|-
 
|-
 
|Development
 
|Development
|Acquirer, suppliers (technical domains for components realization), design engineers, integration team, etc.
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|Acquirer, subject matter experts (SMEs), system architects, design engineers, suppliers, procurement, suppliers (technical domains for components realization), integration team
 
|-
 
|-
|Transfer for Production or for Use
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|Production, Integration, Verification and Validation
|Quality control, production system, operators, etc.
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|Production organization, process engineers, quality control, production verification, product acceptance, supply chain, test engineers, system integration engineers, system verification engineers, system validation engineers, operators/users, owners of enabling systems, facility personnel, contracting, approving authorities, regulators, safety personnel, security personnel
 
|-
 
|-
 
|Logistics and Maintenance
 
|Logistics and Maintenance
|Supply chain, support services, trainers, etc.
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|Customer/technical support, replacement part providers, service technicians, trainers, IT, quality engineer, inspectors, those conducting post development system verification and system validation activities
 
|-
 
|-
 
|Operation
 
|Operation
Line 60: Line 68:
 
|-
 
|-
 
|Disposal
 
|Disposal
|Operators, certifying body, etc.
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|Operators, waste management, regulators, public
|}
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|}
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A key part of stakeholder identification is to determine who the approving authorities are within the group of stakeholders.  It cannot be assumed that the only stakeholder that has this authority is the "customer". The approving authorities include stakeholders that are responsible for formally certifying, qualifying, and approving the system for use in its operational environment by its intended users.  There can be approving authorities both within and external to the organization, especially for highly-regulated systems.
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An approach for recording the list of stakeholders is to use a stakeholder register that includes key information for each stakeholder and how they are involved with the SoI. It is recommended that the project team re-evaluate the stakeholder community periodically to ensure successful engagement with stakeholders, keeping them engaged across all life cycle activities, and managing changes in stakeholders and their needs.
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=== Stakeholder Needs Elicitation ===
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For stakeholder needs elicitation, the project team engages the stakeholders to understand their needs, requirements, and expectations for all life cycle stages. The elicitation activities allow the project team to discover what is needed, what processes exist, how stakeholders interact with the SoI, what happens over the SoI’s life cycle from their perspective (examples are provided below). 
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It is recommended that several techniques or methods be considered during elicitation activities to better accommodate the diverse set of sources (INCOSE NRM 2022):
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* structured brainstorming workshops,
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* interviews and questionnaires,
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* workshops or focus groups,
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* use of visual and descriptive content associated with the SoI,
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* technical, operational, and/or strategy documentation review, and
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* feedback from [[System Verification]] and [[System Validation]] processes.
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A broad range of topics are discussed with the stakeholders:
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* Obtain feedback on the outputs from the Business and Mission Analysis process (problem, threat, opportunity, MGOs, etc.).
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* Identify the life cycle stages the stakeholder represents and their role.
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* For each life cycle stage, obtain input on expected and off-nominal use cases, scenarios, misuse cases, and loss scenarios.
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* Identify the desired capabilities and functions from their perspective.
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* Identify interactions with external systems.
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* Obtain input on their view of quality and other "ilities", such as reliability, testability, serviceability, etc.
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* Inquire about their view of risks and hazards, along with likelihood and consequence.
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* For each need, capture rationale concerning "why".
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* Ask about criticality of the stated needs and relative priorities of all inputs obtained.
  
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During elicitation activities, it is important to ask the stakeholders to provide rationale for and prioritize what they are asking for.  Some needs will be especially important to the stakeholder, while others may be “nice-to-haves” and not critical to the system being able to accomplish its intended use.  There will be some things that the stakeholder may be able to “live without” given budget or schedule constraints.  Providing rationale often reveals the real need, especially when the stakeholder expresses a need as an implementation.
  
There are many ways to collect stakeholder needs, expectations, and objectives. Some of the most common techniques are interviews (including user surveys); technical, operational, and strategy document reviews; analysis of potential hazards and threats coming from the context of use of the system; feedback from [[System Verification|verification]] and [[System Validation|validation]] processes; and review of the outcomes from the [[System Analysis|system analysis]] process (ISO/IEC 2008)Stakeholder requirements are developed from these needs.
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The information obtained from the elicitation activities needs to be recorded with trace to the stakeholder register. In a [[Model-Based Systems Engineering (MBSE)]] effort, the elicited needs can be included in the MBSE system model and traced to the stakeholders.   
  
===Classification of Stakeholder Requirements===
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=== Identify Drivers and Constraints ===
Several classifications of stakeholder requirements are possible, e.g. ISO/IEC 29148, section 9.4.2.3 (ISO/IEC 2011) provides a useful set of elements for classification. One possible way to classify the stakeholder requirements is under the categories indicated in Table 2.
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Drivers and constraints are things outside of the project’s control that constrain or drive the solution space.  Drivers and Constraints can include design constraints (parts, materials, organizational design best practices, etc.), design standards, production constraints (existing technology, facilities, equipment, cost, throughput, etc.), human factors, (human/machine interface - HMI), regulations (law), operating environment (natural, induced), other environment (social, cultural), existing systems: (interactions, interfaces, dependencies), technology maturity, cost, schedule.
  
<center>
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Concurrently with the stakeholder elicitation activities, drivers and constraints need to be identified and recorded within the SoI’s integrated dataset.
{|
 
|+'''Table 2.  Example of Stakeholder Requirements Classification.''' (SEBoK Original)
 
!Type of Stakeholder Requirement
 
!Description
 
|-
 
|'''Service or Functional'''
 
|Sets of actions to perform the mission or operation of the system-of-interest; enhanced by effectiveness or performance characteristics attached to the mission or operations.
 
|-
 
|'''Operational'''
 
|This category may include:
 
*Operational concept that indicates the operational features to be provided without specifying design solutions;
 
*Operational scenarios describing the sequence or series of activities supported by the system-of-interest;
 
*Operational modes and transitions of modes between states/modes of the system-of-interest during its utilization to include dynamic interactions between the system-of-interest (viewed as a black box) and the system-of-interest's interface with external components in the context of its use.
 
|-
 
|'''Interface'''
 
|Matter, energy, or information flows exchanged between the system-of-interest and its external components in the context of its use, including physical interfaces.
 
|-
 
|'''Environmental'''
 
|External conditions affecting the system when in operation.
 
|-
 
|'''Utilization Characteristics'''
 
|The '-ilities' used to indicate conditions of the utilization of the system-of-interest (e.g. usability, dependability, security, etc.)
 
|-
 
|'''Human Factors'''
 
|Capabilities of users and operators, ergonomics, and associated constraints.
 
|-
 
|'''Logistical'''
 
|Acquisition, transportation, and storage of elements needed by the system-of-interest to perform its services (e.g. constraints for logistical support).
 
|-
 
|'''Design and Realization Constraints'''
 
|Re-use of existing system elements or forbidden materials, for example.
 
|-
 
|'''Process Constraints'''
 
|These are stakeholder (usually acquirer or user) requirements imposed through the contract or statement of work. These requirements do not directly address the end-item system, but rather ''how'' the end-item system is developed and provided. Process requirements include compliance with national, state, or local laws, including environmental laws; administrative requirements; acquirer/supplier relationship requirements; and specific work directives. Process requirements may also be imposed on a program by corporate policy or practice. System or system element implementation process requirements, such as mandating a particular design method, are usually captured in project agreement documentation such as contracts, statements of work (SOW), and quality plans.
 
|-
 
|'''Project Constraints'''
 
|Constraints to performing the project and/or the end-item system within cost and schedule.
 
|-
 
|'''Business Model Constraints'''
 
|Constraints related to the expected business goal achieved by the system-of-interest, when this is relevant within the context of use; these may include geographic position (local, national, international) of the future product, service, or organization resulting from the system-of-interest, distribution channels, alliance and partnership, finance and revenue model etc.
 
|}
 
</center>
 
  
==Process Approach==
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=== Identify, Assess, and Handle Risk ===
  
===Activities of the Process===
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Risks are anything that could prevent the delivery of a successful SoI (providing what is needed, within budget and schedule, with the needed quality), anything that could impact the intended use of the SoI in its intended environment by its intended users, or anything that would allow unintended users to prevent the intended use of the SoI or to use the SOI in an unintended manner, e.g., hack into an aircraft and use the aircraft as a weapon.  
Major activities and tasks performed during this process include the following:
 
*Identify the stakeholders or classes of stakeholders across the life cycle;
 
*Elicit, capture, or consolidate the stakeholders' needs, expectations, and objectives as well as any constraints coming from the mission and business analysis processes;
 
*Prioritize the stakeholder needs;
 
*Transform the prioritized and retained stakeholder needs into stakeholder requirements;
 
*Verify the quality of each stakeholder requirement and of the set of stakeholder requirements using the characteristics of good requirements identified in Tables 4 and 5 in [[System Requirements]];
 
*Validate the content and the relevance of each stakeholder requirement with corresponding stakeholder representatives providing [[Rationale (glossary)|rationale (glossary)]] for the existence of the requirement;
 
*Identify potential [[Risk (glossary) |risks]] (or threats and hazards) that could be generated by the stakeholder requirements (for further information, see [[Risk Management]]); and
 
*Synthesize, record, and manage the stakeholder requirements and potential associated risks.
 
  
===Artifacts and Ontology Elements===
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As part of the elicitation activities, issues and risks must be identified and assessed. The identified risks from the Business or Mission Analysis effort should be used as a starting point, and then additional elaboration of risks is needed along with how the project is expected to handle those risks. Stakeholders should be asked specifically about any issues and risk they think could prevent the SoI to be developed and delivered within budget, schedule, or risk during operations.  Failing to address risk will result in an incomplete set of needs and resulting design input requirements resulting in a SoI that will fail [[System Validation|system validation]].  
This process may create several artifacts, such as
 
*stakeholder requirements documents;
 
*stakeholder interview reports;
 
*stakeholder requirements database; and
 
*stakeholder requirements justification documents (for traceability purposes).
 
  
This process utilizes the ontology elements of Table 3.
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The project must do a risk assessment of each of the risks (see [[Risk Management]]).  Some risks could lead to development of life cycle concepts as part of the mitigation (such as for hazards), which are expanded further in the next section.
  
<center>
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=== Life Cycle Concepts Analysis and Maturation ===
{|
 
|+'''Table 3. Main Ontology Elements as Handled within Stakeholder Requirements Definition.''' (SEBoK Original)
 
!Element
 
!Definition Attributes (examples)
 
|-
 
|'''Stakeholder'''
 
|Party having a right, share, or claim in a system or in its possession of characteristics that meets that party's needs and expectations (ISO/IEC 2008). N.B.: Stakeholders include, but are not limited to, end users, end user organizations, supporters, developers, producers, trainers, maintainers, disposers, acquirers, customers, operators, supplier organizations, and regulatory bodies. (ISO/IEC 2011)
 
----
 
Identifier; name; description; status (identified, interviewed)
 
|-
 
|'''Stakeholder Requirement'''
 
|Necessity or desire expected by an end user, formally drafted and expressed in terms of a client and end user; service, objective, capability expected from the future system by the end users. Equivalent to expectation; includes user requirements.
 
----
 
Identifier; name; description; origin (the owner of the expression of the stakeholder requirement); type (classification); flexibility (possibilities for negotiation - possibly supplemented with a margin rate); priority (immediately satisfied, allocated to a later version, etc.); decision (result of a trade-off study having led to choosing or rejecting the requirement); status (proposed, in review, validated, deleted, etc.); history records (date, author, identification, and contents of the modification, type of modification, reason for the modification); comment.
 
|-
 
|'''Rationale'''
 
|Argument that provides the justification for the selection of an engineering element.
 
----
 
Identifier; name; description (rational, reasons for a requirement to be satisfied)
 
|-
 
|'''Scenario'''
 
|A set of actions/functions representing the dynamic of exchanges between the functions allowing the system to achieve a mission or a service.
 
----
 
Identifier; name; description
 
|-
 
|'''Risk'''
 
|An event having a probability of occurrence and a gravity degree on its consequence onto the system mission or on other properties (used for technical risk in engineering). A risk is the combination of vulnerability and of a danger or a threat.
 
----
 
Identifier; name; description; status
 
|}
 
</center>
 
  
===Methods and Modeling Techniques===
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As a result of life cycle concept analysis and maturation activities, architectural and analytical/behavioral models are developed.  Based on the resulting information, the preliminary set of life cycle {{term|Operational Concept (glossary)|concepts}} established in [[Business or Mission Analysis]] are transformed into a mature set of life cycle concepts that are consistent, correct, complete, and feasible.  Models and diagrams (such as those used in [[Model-Based Systems Engineering (MBSE)]] are excellent analysis tools for defining and maturing feasible life cycle concepts by providing a context for needs, and are key to help ensure correctness, completeness, and consistency of both individual needs and the integrated set of needs.
It is recommended that several techniques or methods for identifying needs, expectations, and requirements be considered during the elicitation activity to better accommodate the diverse set of requirements sources, including
 
*structured brainstorming workshops;
 
*interviews and questionnaires;
 
*technical, operational, and/or strategy documentation review;
 
*simulations and visualizations;
 
*prototyping;
 
*modeling;
 
*quality function deployment (QFD), which can be used during the needs analysis and is a technique for deploying the "voice of the customer”. It provides a fast way to translate customer needs into requirements;
 
*use case diagrams (OMG 2010);
 
*activity diagrams (OMG 2010); and
 
*functional flow block diagrams.
 
  
==Practical Considerations==
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The {{Term|Logical Architecture (glossary)}} defines {{term|System Boundary (glossary)|system boundary}} and {{term|Function (glossary)|functions}}, from which more detailed needs can be determined (interactions and interdependencies between logical elements of the system).  As part of life cycle concept maturation, functions are defined, grouped logically, and relationships and interactions between those functions are captured. Supporting analytical and behavioral models can be developed to help assess behavior, interactions between parts of the architecture, and determine the performance characteristics of the functions.  
Major pitfalls encountered with stakeholder requirements are presented in Table 4.
 
  
<center>
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=== Define and Baseline the Integrated Set of Needs ===
{|
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The project team derives an integrated set of needs that reflect the set of feasible system life cycle concepts, MGOs, measures, business operations level and system level stakeholder needs, drivers and constraints, and risk mitigation (Figure 4).  These outcomes include results of the life cycle concepts analysis and maturation activity to determine expected functionality (what the stakeholders need the system to do), expected performance and quality (“how well” characteristics), the conditions of action, including triggering events, system states, and operating environments (“under what operating conditions”), as well as compliance with standards and regulations.  
|+'''Table 4. Major Pitfalls for Stakeholder Requirements.''' (SEBoK Original)
 
!Pitfall
 
!Description
 
|-
 
|'''Operator role not considered'''
 
|Sometimes engineers do not take into account the humans acting as operators inside a system or those who use the system and are outside of the system. In consequence, elements are forgotten (e.g. roles of operators).
 
|-
 
|'''Exchanges with external objects forgotten'''
 
|The exhaustiveness of requirements is an issue; in particular, the interfaces with external objects of the context of the system can be forgotten (exchanges of matter, energy, information).
 
|-
 
|'''Physical connections with external objects forgotten'''
 
|Within the interface issue, physical connections of the stem-of-interest with external objects can be forgotten (technological constraints).
 
|-
 
|'''Forgotten stakeholders'''
 
|Stakeholders can be forgotten; everyone thinks of direct users, customers, and suppliers, but those who do not want the system to exist and malevolent persons are often left out.
 
|}
 
</center>
 
  
 +
[[File:Figure StkhldrNeeds-4 from INCOSE NRM.jpg|thumb|900px|center|'''Figure 4. Input into the integrated set of needs.''' This figure is reprinted with permission of Lou Wheatcraft. All other rights are reserved by the copyright owner.]]
  
Proven practices with stakeholder requirements are presented in Table 5.
+
This integrated set of needs is what will be transformed into the set of design input requirements. In addition, it is this integrated set of needs which the design input requirements, design, and realized system will be validated against.  
  
<center>
+
Needs are written in a structured, natural language from the perspective of what the stakeholders need the SoI to do. To help distinguish needs from the requirements, the needs statements do not include the word “shall” (or other word that depicts the statement is a requirement). It is recommended that need statements use a different format from requirements, such as: “The stakeholders need the system to” (INCOSE GtWR 2023).  See Table 2 for example need statements.
{|
+
{| class="wikitable"
|+'''Table 5. Stakeholder Requirements Proven Practices.''' (SEBoK Original)
+
|+'''Table 2. Example Need Statements.''' (SEBoK Original)
!Practice
+
!ID
!Description
+
!Name
 +
!Need Statement
 +
!Rationale
 +
!Source
 
|-
 
|-
|'''Involve stakeholders'''
+
|N1
|Involve the stakeholders early in the stakeholder requirements development process.
+
|Variable Temperature Settings.
 +
|The user needs the coffee maker to have two temperature settings (warm and  hot) for the water temperature.
 +
|Focus groups provided input that a multi-select option for temperature is  a desired feature.
 +
|Consumer input
 
|-
 
|-
|'''Presence of rationale'''
+
|N2
|Capture the rationale for each stakeholder requirement.
+
|Prohibit Brew if Container Missing
 +
|The user needs the coffee maker to not brew unless a coffee container is  in place.
 +
|Mitigation of risk of user error prior to starting coffee maker brew  process.
 +
|Risk mitigation
 
|-
 
|-
|'''Analyze sources before starting'''
+
|N3
|Complete stakeholder requirements as much as possible for starting the definition of the system requirements.
+
|Coffee Maker Color Options
 +
|The company stakeholders need the coffee maker to come in four colors:  black, grey, blue and red.
 +
|Marketing survey found that offering multiple colors provides competitive  advantage with consumers.
 +
|Marketing stakeholder
 
|-
 
|-
|'''Modeling techniques'''
+
|N4
|Use modeling techniques as indicated in sections above.
+
|Ease of Use
|-
+
|The user needs the coffee maker to be easy to use (clearly defined user interface and a minimum of steps to get a cup of coffee).
|'''Requirements management tool'''
+
|Focus groups provided input that they are more likely to purchase  products with simple user interfaces and operation controls.
|Consider using a requirements management tool. This tool should have the capability to trace linkages between the stakeholder requirements and the system requirements and to record the source of each stakeholder requirement.
+
|Consumer input
 
|}
 
|}
</center>
+
The integrated set of needs must be recorded within the SoI’s integrated dataset in a form and media suitable for review and feedback from the stakeholders, as well as a form that allows traceability.  It is critical that the project team has confirmation from the stakeholders that their needs, requirements, expectations, MGOs, measures, drivers and constraints, and risk are properly communicated by integrated set of needs, this is supported by traceability.  In a {{term|Model-Based Systems Engineering (MBSE) (glossary)|model-based systems engineering (MBSE)}} approach, the needs can be included in the system model, where they can be traced to their source (life cycle, stakeholder, MGO, risk, etc.).
 +
 
 +
Once the integrated set of needs is captured, they are used as inputs into the [[System Requirements Definition]] process.
  
 
==References==
 
==References==
 
===Works Cited===
 
===Works Cited===
Faisandier, A. 2012. Systems Architecture and Design. Belberaud, France: Sinergy'Com.
 
  
OMG. 2010. ''OMG Systems Modeling Language specification'', version 1.2, July 2010. http://www.omg.org/technology/documents/spec_catalog.htm.
+
INCOSE. 2022. ''INCOSE Needs and Requirements Manual'', version 1.1. INCOSE-TP-2021-002-01.
  
ISO/IEC/IEEE. 2011. Systems and software engineering - Requirements engineering. Geneva, Switzerland: International Organization for Standardization (ISO)/International Electrotechnical Commission/ Institute of Electrical and Electronics Engineers (IEEE), (IEC), ISO/IEC/IEEE 29148.
+
INCOSE. 2022. ''INCOSE Guide to Needs and Requirements'', version 1. INCOSE-TP-2021-003-01.
  
ISO/IEC/IEEE. 2008. ''Systems and Software Engineering - System Life Cycle Processes.'' Geneva, Switzerland: International Organization for Standardization (ISO)/International Electronical Commission (IEC), Institute of Electrical and Electronics Engineers. ISO/IEC/IEEE 15288:2008 (E).
+
INCOSE. 2023. ''INCOSE Guide to Writing Requirements (GtWR)'', version 4. INCOSE-TP-2006-004-04.
  
 
===Primary References===
 
===Primary References===
ISO/IEC/IEEE. 2011. ''[[ISO/IEC/IEEE 29148|Systems and software engineering - Requirements engineering]]''. Geneva, Switzerland: International Organization for Standardization (ISO)/International Electrotechnical Commission/ Institute of Electrical and Electronics Engineers (IEEE), (IEC), ISO/IEC/IEEE 29148.
+
INCOSE. 2022. ''INCOSE Needs and Requirements Manual'', version 1.1. INCOSE-TP-2021-002-01.
  
ISO/IEC/IEEE. 2008. ''[[ISO/IEC/IEEE 15288|Systems and Software Engineering - System Life Cycle Processes]].'' Geneva, Switzerland: International Organization for Standardization (ISO)/International Electronical Commission (IEC), Institute of Electrical and Electronics Engineers. [[ISO/IEC/IEEE 15288]]:2008 (E).
+
INCOSE. 2022. ''INCOSE Guide to Needs and Requirements'', version 1. INCOSE-TP-2021-003-01.
  
ISO/IEC/IEEE. 2011. ''[[ISO/IEC/IEEE 42010|Systems and Software Engineering - Architecture Description]]''. Geneva, Switzerland: International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC)/Institute of Electrical and Electronics Engineers (IEEE), [[ISO/IEC/IEEE 42010]].
+
INCOSE. 2023. ''Systems Engineering Handbook: A Guide for System Life Cycle Processes and Activities'', version 5.0. Hoboken, NJ, USA: John Wiley and Sons, Inc, ISBN: 978-1-118-99940-0.
  
===Additional References===
+
ISO/IEC/IEEE. 2018. ''Systems and software engineering - Requirements engineering.'' Geneva, Switzerland: International Organization for Standardization (ISO)/International Electrotechnical Commission/ Institute of Electrical and Electronics Engineers (IEEE), (IEC), ISO/IEC/IEEE 29148.
Buede, D.M. 2009. ''The engineering design of systems: Models and methods''. 2nd ed. Hoboken, NJ, USA: John Wiley & Sons Inc.  
 
  
MITRE.  2011. "Requirements Engineering.''Systems Engineering Guide. '' Accessed 9 March 2012 at [[http://www.mitre.org/work/systems_engineering/guide/se_lifecycle_building_blocks/requirements_engineering/]].
+
ISO/IEC/IEEE. 2023. ''[[ISO/IEC/IEEE 15288|Systems and Software Engineering -- System Life Cycle Processes]]''. Geneva, Switzerland: International Organisation for Standardisation / International Electrotechnical Commissions / Institute of Electrical and Electronics Engineers. ISO/IEC/IEEE 15288:2015.
  
MITRE. 2011. "Stakeholder Assessment and Management."  ''Systems Engineering Guide. '' Accessed 9 March 2012 at [[http://www.mitre.org/work/systems_engineering/guide/enterprise_engineering/transformation_planning_org_change/stakeholder_assessment_management.html]].
+
===Additional References===
 +
INCOSE. 2023. ''INCOSE Guide to Writing Requirements'', version 4. INCOSE-TP-2006-004-01.
 +
===Relevant Videos===
 +
*[https://youtu.be/hEGfNLvuyXo?list=PLVfZ7HbxxzBVnavoSAMUXjP49triK36KN INCOSE Webinar, Life cycle Concepts and Needs Definition]
 +
*[https://www.youtube.com/watch?v=YJ4wCbKJeXY How to Get Project Requirements from Project Stakeholders]
 
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<center>[[Mission Analysis|< Previous Article]] | [[Concept Definition|Parent Article]] | [[System Definition|Next Article >]]</center>
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<center>[[Business or Mission Analysis|< Previous Article]] | [[System Concept Definition|Parent Article]] | [[System Requirements Definition|Next Article >]]</center>
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 +
<center>'''SEBoK v. 2.10, released 06 May 2024'''</center>
  
[[Category:Concept Definition]]
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[[Category: Part 3]][[Category:Topic]]
{{DISQUS}}
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[[Category:System Concept Definition]]

Latest revision as of 23:20, 2 May 2024


Lead Author: Tami Katz, Contributing Authors: Lou Wheatcraft, Mike Ryan


Stakeholder Needs Definition, the second process in Concept Definition, explores what capabilitiescapabilities are needed by various stakeholders for the system-of-interestsystem-of-interest (SoI) to accomplish the mission. The outcome of the Stakeholder Needs Definition process is used as the basis of System Validation, as well as input into the System Requirements Definition process.

Note that the first process, Business or Mission Analysis, is often performed iteratively with Stakeholder Needs Definition to better understand the problem, threat, or opportunity space, as well as options of the solution space.

Purpose and Definition

Stakeholder needsStakeholder needs represent a user, acquirer, customer, and other stakeholdersstakeholders perspective of the SoI, which are then transformed into system requirementssystem requirements which communicate a developer perspective of the SoI. When stakeholder needs are combined with results of multiple analysis activities that includes risks, drivers, constraints, and life cycle concepts analysis, as shown in Figure 1, the result is an overall integrated set of needs.

Figure 1. Establishment of an Integrated Set of Needs ensures that all perspectives are analyzed during the Stakeholder Need Definition process, including risks, drivers, constraints, and life cycle concepts analysis and maturation. This figure is reprinted with permission of Lou Wheatcraft and Mike Ryan. All other rights are reserved by the copyright owner.

The establishment of the integrated set of needs forms the basis of a full understanding of the capabilities expected of the SoI, and these needs are ultimately transformed into a set of design-input requirements on the SoI as part of the System Requirements Definition process.

Principles and Concepts

The results of the Business or Mission Analysis is provided as inputs into the Stakeholder Needs Definition process (shown in Figure 2). This input includes the problem, threat or opportunity statement capturing why the project is worth doing, the mission, goals and objectives (MGOs) and measures of success used as the criteria for assessing project success, along with identification of major stakeholders, initial life cycle concepts, and initial concepts of the solution space (architecture and design).

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Figure 2. Stakeholder Needs Definition expands upon the Business or Mission Analysis results to refine the set of needs for the System of Interest. (SEBoK Original)

The Stakeholder Needs Definition process continues the life cycle concepts definition activities to ensure the system-of-interest (SoI)system-of-interest (SoI) provides the capabilities needed by users and other stakeholders in the intended operational environment. This process is much more than identification and elicitation of need or requirement statements from various stakeholders, it consists of a series of analysis activities done to ensure that all parameters are captured, including risks, drivers, constraints, as well as the SoI life cycle concepts analysis and maturation; this effort results in an integrated set of needs as shown in Figure 3.

Figure 3. Establishment of an integrated set of needs ensures that all perspectives are analyzed during the Stakeholder Need Definition process, including risks, drivers, constraints, and life cycle concepts analysis and maturation. This figure is reprinted with permission of Lou Wheatcraft. All other rights are reserved by the copyright owner.

The result of this process is a well-formed integrated set of needs that is correct, consistent, complete, and feasible. It is this set of needs that defines the scope of the project which the organization agrees to provide the resources necessary for developing the SoI, and against which the requirements, design, and the realized SoI will be validated against.

Nomenclature discussion

This process is frequently referred to as the "Stakeholder Needs and Requirements" process. Because various guides, textbooks, and standards refer to stakeholder “expectations, needs, and requirements” as if they are the same, resulting in confusion as to what is an “expectation” versus a “need” and a “requirement”, this article focuses on the process of developing an integrated set of stakeholder needs. The term "stakeholder requirements" is considered a set of requirements on the SoI established by the stakeholder, as transformed from their needs, which are provided as additional input towards the life cycle concepts analysis and maturation activities from which the integrated set of needs is defined. In Figure 3, this is designated as both "stakeholder needs, requirements, and expectations" as well as the "higher-level requirements" inputs.

Process Approach

Inputs to the Stakeholder Needs Definition Process

The inputs from the Business or Mission Analysis process includes identification of major stakeholders, definition of the problem, threat, or opportunity, elaboration of the MGOs and measures of success, capture of preliminary life cycle concepts, and identification of initial concepts of the solution space (architecture and design).

Activities of the Process

There are several activities performed during this process:

  • Identify additional stakeholders or classes of stakeholders across the life cycle.
  • Elicit, capture, consolidate and prioritize stakeholder needs, requirements, and expectations.
  • Identify drivers and constraints on the SoI and its development efforts.
  • Identify potential risksrisks (such as threats and hazards) that could prevent the SoI from successful operation (see Risk Management for further information on addressing risks).
  • Mature and analyze the life cycle concepts.
  • Identify, baseline, and manage the integrated set of needs.

The activities behind each of these are described in the following sections.

Identify Stakeholders

Stakeholders are the primary source of needs and requirements, therefore for the project to be successful, all relevant stakeholders must be identified and included from the beginning of the project. Leaving out a relevant stakeholder often results in missing needs and requirements and a failure to pass system validation.  Stakeholders can include, but are not limited to, customers, sponsors, organization decision makers, regulatory organizations, developing organizations, integrators, testers, users, operators, maintainers, support organizations, the public at large (within the context of the business and proposed solution), and those involved in the disposal or retirement of the SoI.  Stakeholders can be both internal and external to the organization. There can be many stakeholders for a SoI over its life cycle; therefore, considering the life cyclelife cycle concepts provides a thorough source for stakeholder identification. Examples of stakeholders are provided in Table 1.

Table 1. Stakeholder Identification Based on Life Cycle Stages. (SEBoK Original)
Life Cycle Stage Example of Related Stakeholders
Concept Paying customer, sponsor, project team, project manager, procurement, research and development, suppliers, regulating authorities, public, marketing, end users, operators, compliance office, regulators, owners of enabling systems, owners of external systems, Approving Authorities
Development Acquirer, subject matter experts (SMEs), system architects, design engineers, suppliers, procurement, suppliers (technical domains for components realization), integration team
Production, Integration, Verification and Validation Production organization, process engineers, quality control, production verification, product acceptance, supply chain, test engineers, system integration engineers, system verification engineers, system validation engineers, operators/users, owners of enabling systems, facility personnel, contracting, approving authorities, regulators, safety personnel, security personnel
Logistics and Maintenance Customer/technical support, replacement part providers, service technicians, trainers, IT, quality engineer, inspectors, those conducting post development system verification and system validation activities
Operation Normal users, unexpected users, etc.
Disposal Operators, waste management, regulators, public

A key part of stakeholder identification is to determine who the approving authorities are within the group of stakeholders.  It cannot be assumed that the only stakeholder that has this authority is the "customer". The approving authorities include stakeholders that are responsible for formally certifying, qualifying, and approving the system for use in its operational environment by its intended users. There can be approving authorities both within and external to the organization, especially for highly-regulated systems.

An approach for recording the list of stakeholders is to use a stakeholder register that includes key information for each stakeholder and how they are involved with the SoI. It is recommended that the project team re-evaluate the stakeholder community periodically to ensure successful engagement with stakeholders, keeping them engaged across all life cycle activities, and managing changes in stakeholders and their needs.

Stakeholder Needs Elicitation

For stakeholder needs elicitation, the project team engages the stakeholders to understand their needs, requirements, and expectations for all life cycle stages. The elicitation activities allow the project team to discover what is needed, what processes exist, how stakeholders interact with the SoI, what happens over the SoI’s life cycle from their perspective (examples are provided below).

It is recommended that several techniques or methods be considered during elicitation activities to better accommodate the diverse set of sources (INCOSE NRM 2022):

  • structured brainstorming workshops,
  • interviews and questionnaires,
  • workshops or focus groups,
  • use of visual and descriptive content associated with the SoI,
  • technical, operational, and/or strategy documentation review, and
  • feedback from System Verification and System Validation processes.

A broad range of topics are discussed with the stakeholders:

  • Obtain feedback on the outputs from the Business and Mission Analysis process (problem, threat, opportunity, MGOs, etc.).
  • Identify the life cycle stages the stakeholder represents and their role.
  • For each life cycle stage, obtain input on expected and off-nominal use cases, scenarios, misuse cases, and loss scenarios.
  • Identify the desired capabilities and functions from their perspective.
  • Identify interactions with external systems.
  • Obtain input on their view of quality and other "ilities", such as reliability, testability, serviceability, etc.
  • Inquire about their view of risks and hazards, along with likelihood and consequence.
  • For each need, capture rationale concerning "why".
  • Ask about criticality of the stated needs and relative priorities of all inputs obtained.

During elicitation activities, it is important to ask the stakeholders to provide rationale for and prioritize what they are asking for.  Some needs will be especially important to the stakeholder, while others may be “nice-to-haves” and not critical to the system being able to accomplish its intended use.  There will be some things that the stakeholder may be able to “live without” given budget or schedule constraints. Providing rationale often reveals the real need, especially when the stakeholder expresses a need as an implementation.

The information obtained from the elicitation activities needs to be recorded with trace to the stakeholder register. In a Model-Based Systems Engineering (MBSE) effort, the elicited needs can be included in the MBSE system model and traced to the stakeholders.

Identify Drivers and Constraints

Drivers and constraints are things outside of the project’s control that constrain or drive the solution space.  Drivers and Constraints can include design constraints (parts, materials, organizational design best practices, etc.), design standards, production constraints (existing technology, facilities, equipment, cost, throughput, etc.), human factors, (human/machine interface - HMI), regulations (law), operating environment (natural, induced), other environment (social, cultural), existing systems: (interactions, interfaces, dependencies), technology maturity, cost, schedule.

Concurrently with the stakeholder elicitation activities, drivers and constraints need to be identified and recorded within the SoI’s integrated dataset.

Identify, Assess, and Handle Risk

Risks are anything that could prevent the delivery of a successful SoI (providing what is needed, within budget and schedule, with the needed quality), anything that could impact the intended use of the SoI in its intended environment by its intended users, or anything that would allow unintended users to prevent the intended use of the SoI or to use the SOI in an unintended manner, e.g., hack into an aircraft and use the aircraft as a weapon.

As part of the elicitation activities, issues and risks must be identified and assessed. The identified risks from the Business or Mission Analysis effort should be used as a starting point, and then additional elaboration of risks is needed along with how the project is expected to handle those risks. Stakeholders should be asked specifically about any issues and risk they think could prevent the SoI to be developed and delivered within budget, schedule, or risk during operations.  Failing to address risk will result in an incomplete set of needs and resulting design input requirements resulting in a SoI that will fail system validation.

The project must do a risk assessment of each of the risks (see Risk Management).  Some risks could lead to development of life cycle concepts as part of the mitigation (such as for hazards), which are expanded further in the next section.

Life Cycle Concepts Analysis and Maturation

As a result of life cycle concept analysis and maturation activities, architectural and analytical/behavioral models are developed.  Based on the resulting information, the preliminary set of life cycle conceptsconcepts established in Business or Mission Analysis are transformed into a mature set of life cycle concepts that are consistent, correct, complete, and feasible.  Models and diagrams (such as those used in Model-Based Systems Engineering (MBSE) are excellent analysis tools for defining and maturing feasible life cycle concepts by providing a context for needs, and are key to help ensure correctness, completeness, and consistency of both individual needs and the integrated set of needs.

The logical architecturelogical architecture defines system boundarysystem boundary and functionsfunctions, from which more detailed needs can be determined (interactions and interdependencies between logical elements of the system). As part of life cycle concept maturation, functions are defined, grouped logically, and relationships and interactions between those functions are captured. Supporting analytical and behavioral models can be developed to help assess behavior, interactions between parts of the architecture, and determine the performance characteristics of the functions.  

Define and Baseline the Integrated Set of Needs

The project team derives an integrated set of needs that reflect the set of feasible system life cycle concepts, MGOs, measures, business operations level and system level stakeholder needs, drivers and constraints, and risk mitigation (Figure 4).  These outcomes include results of the life cycle concepts analysis and maturation activity to determine expected functionality (what the stakeholders need the system to do), expected performance and quality (“how well” characteristics), the conditions of action, including triggering events, system states, and operating environments (“under what operating conditions”), as well as compliance with standards and regulations.

Figure 4. Input into the integrated set of needs. This figure is reprinted with permission of Lou Wheatcraft. All other rights are reserved by the copyright owner.

This integrated set of needs is what will be transformed into the set of design input requirements. In addition, it is this integrated set of needs which the design input requirements, design, and realized system will be validated against.

Needs are written in a structured, natural language from the perspective of what the stakeholders need the SoI to do. To help distinguish needs from the requirements, the needs statements do not include the word “shall” (or other word that depicts the statement is a requirement). It is recommended that need statements use a different format from requirements, such as: “The stakeholders need the system to” (INCOSE GtWR 2023). See Table 2 for example need statements.

Table 2. Example Need Statements. (SEBoK Original)
ID Name Need Statement Rationale Source
N1 Variable Temperature Settings. The user needs the coffee maker to have two temperature settings (warm and hot) for the water temperature. Focus groups provided input that a multi-select option for temperature is a desired feature. Consumer input
N2 Prohibit Brew if Container Missing The user needs the coffee maker to not brew unless a coffee container is in place. Mitigation of risk of user error prior to starting coffee maker brew process. Risk mitigation
N3 Coffee Maker Color Options The company stakeholders need the coffee maker to come in four colors: black, grey, blue and red. Marketing survey found that offering multiple colors provides competitive advantage with consumers. Marketing stakeholder
N4 Ease of Use The user needs the coffee maker to be easy to use (clearly defined user interface and a minimum of steps to get a cup of coffee). Focus groups provided input that they are more likely to purchase products with simple user interfaces and operation controls. Consumer input

The integrated set of needs must be recorded within the SoI’s integrated dataset in a form and media suitable for review and feedback from the stakeholders, as well as a form that allows traceability.  It is critical that the project team has confirmation from the stakeholders that their needs, requirements, expectations, MGOs, measures, drivers and constraints, and risk are properly communicated by integrated set of needs, this is supported by traceability. In a model-based systems engineering (MBSE)model-based systems engineering (MBSE) approach, the needs can be included in the system model, where they can be traced to their source (life cycle, stakeholder, MGO, risk, etc.).

Once the integrated set of needs is captured, they are used as inputs into the System Requirements Definition process.

References

Works Cited

INCOSE. 2022. INCOSE Needs and Requirements Manual, version 1.1. INCOSE-TP-2021-002-01.

INCOSE. 2022. INCOSE Guide to Needs and Requirements, version 1. INCOSE-TP-2021-003-01.

INCOSE. 2023. INCOSE Guide to Writing Requirements (GtWR), version 4. INCOSE-TP-2006-004-04.

Primary References

INCOSE. 2022. INCOSE Needs and Requirements Manual, version 1.1. INCOSE-TP-2021-002-01.

INCOSE. 2022. INCOSE Guide to Needs and Requirements, version 1. INCOSE-TP-2021-003-01.

INCOSE. 2023. Systems Engineering Handbook: A Guide for System Life Cycle Processes and Activities, version 5.0. Hoboken, NJ, USA: John Wiley and Sons, Inc, ISBN: 978-1-118-99940-0.

ISO/IEC/IEEE. 2018. Systems and software engineering - Requirements engineering. Geneva, Switzerland: International Organization for Standardization (ISO)/International Electrotechnical Commission/ Institute of Electrical and Electronics Engineers (IEEE), (IEC), ISO/IEC/IEEE 29148.

ISO/IEC/IEEE. 2023. Systems and Software Engineering -- System Life Cycle Processes. Geneva, Switzerland: International Organisation for Standardisation / International Electrotechnical Commissions / Institute of Electrical and Electronics Engineers. ISO/IEC/IEEE 15288:2015.

Additional References

INCOSE. 2023. INCOSE Guide to Writing Requirements, version 4. INCOSE-TP-2006-004-01.

Relevant Videos


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SEBoK v. 2.10, released 06 May 2024