The Ultimate Guide to Requirements Management

What Is Requirements Management?

Requirements Management is the process of gathering, documenting, prioritizing, and tracking requirements throughout the lifecycle of a system or product. It involves identifying the needs and expectations of stakeholders, defining the scope of the project or product, and ensuring that these requirements are objectively understandable, feasible, and achievable.

What are the Benefits of Requirements Management?

Doing the hard work of managing requirements properly is worth the effort. Stakeholders will see the following benefits:

1. Enhanced clarity and direction
2. Improved stakeholder communication
3. Mitigated risks
4. Quality assurance
5. Cost and time efficiency
6. Better change management
7. Increased end-user satisfaction
8. Regulatory compliance
9. Improved project outcomes
   

Effective project management is crucial for success in today's dynamic business environment. The key to this success is clear goals. This ensures team alignment, enhanced communication with stakeholders, fostered collaboration and risk mitigation, and quality assurance, ensuring deliverables satisfy stakeholder standards and customer satisfaction.

Cost and time efficiency are vital, ensuring projects stay within budget and time constraints. Adaptability through effective change management keeps projects aligned with business goals despite challenges. The ultimate goal is increasing end-user satisfaction, which drives repeat business and builds long-term client relationships.

Adhering to regulatory compliance is essential for trust and project viability. These efforts lead to improved project outcomes, achieving strategic objectives, and establishing new standards for project excellence.

What Is a Requirement? 

The simple definition of a requirement is  “something that you must do or something you need.” Cambridge Dictionary

All system and product requirements will meet this basic definition. In development, requirements are the statements that describe capabilities, features, functions, and constraints that a system must meet to satisfy stakeholder needs and reach appointed goals. However, it is essential to define requirements into types.

A requirement for a system or product should be more specific. Defining clear and measurable requirements is important because they reduce uncertainty, improve communication, mitigate risks, and increase the likelihood of project success by providing a solid foundation for planning, execution, and evaluation.

Types of Requirements

There are many types of requirements. Here are the most common or useful requirement types.

Environmental

Environmental requirements specify the physical surroundings, climate, regulatory standards, and other external influences that could impact the design, implementation, or operation of the system or product.

Environmental requirements can include specifications related to factors like temperature range, humidity, atmospheric pressure, electromagnetic interference (EMI), radiation exposure, seismic activity, and so on. 

For example, a satellite system might have environmental requirements specifying its ability to withstand the extreme temperatures and vacuum of space, while a medical device might have requirements regarding its performance within certain humidity and temperature ranges.

Functional

Functional requirements specify what the system must do or accomplish. Functional requirements describe the functions, operations, and behaviors the system must fulfill to meet its intended purpose.

Functional requirements are typically distinguished from non-functional requirements, which specify criteria related to the system's operation, performance, security, usability, and other quality attributes.

Interface

Interface requirements detail the inputs, outputs, protocols, formats, timing constraints, and other characteristics necessary for effective communication and interaction between different parts of the system. These requirements are crucial for ensuring interoperability, compatibility, and integration between various system elements.

Interface requirements can include specifications for:

• Physical interfaces
• Software interfaces
• Human-Computer Interfaces
• System-to-System Interfaces

An example of an Interface Requirement 

"The system shall support communication with external servers using the TCP/IP protocol over Ethernet connections, with data exchange occurring at a minimum rate of 1 Mbps."

Performance

Performance requirements specify the criteria that a system must meet in terms of its performance characteristics. These requirements describe how well the system must perform under various conditions, including factors such as speed, throughput, response time, capacity, accuracy, reliability, and efficiency. 

For example, a web server might have performance requirements specifying the maximum number of concurrent users it can support or the response time for serving web pages. In contrast, a medical device might have requirements regarding the accuracy and precision of its measurements within certain timeframes.

Performance requirements are crucial for ensuring that the system meets the expectations of its users and stakeholders.

Reliability

Reliability requirements in requirements management and systems engineering specify the level of dependability, consistency, and availability that a system must exhibit over time and under various operating conditions. These requirements define the system's ability to perform its intended functions without failure and to maintain its performance over its expected lifespan. Reliability requirements are essential for ensuring that the system meets the expectations of its users and stakeholders for uninterrupted operation and minimal downtime.

Reliability requirements can encompass several aspects, including:

• Availability
• Fault Tolerance
• Mean Time Between Failures (MTBF)
• Failure Rate
• Maintainability
• Redundancy
• Continuous Operation
• Safety

Reliability requirements are typically defined in collaboration with stakeholders to align with their expectations for system performance, uptime, and resilience. Verifying reliability requirements often involves testing, analysis, and validation activities to assess the system's ability to meet specified reliability targets.

Related Article: Why Quality Assurance Matters in the Requirements Management Phase

Mission

A mission requirement is a specific, actionable, and measurable objective that must be met to achieve the overall goals of a mission or project. These requirements are critical components in the planning and execution phases of any mission, ensuring that all necessary criteria are fulfilled for successful completion.

Here are some key aspects of mission requirements:

• Specificity
• Measurability
• Achievability
• Relevance
• Time-Bound

In systems engineering and project management, mission requirements guide the development, testing, and implementation processes, ensuring that all aspects of the mission align with the desired outcomes. They serve as a foundation for decision-making and risk management throughout the lifecycle of the mission.

Verification

A verification requirement defines the criteria that a system or component must meet to demonstrate compliance with a specific requirement. Verification requirements specify the conditions or tests that must be satisfied to confirm that the system or component behaves as expected and meets its intended purpose.

Examples of verification requirements include specifying acceptable performance thresholds, defining test cases, identifying acceptance criteria, or outlining simulation parameters to validate a requirement.

Verification method

A verification method requirement specifies the approach or method that will be used to verify or validate a particular requirement. It outlines the procedure or technique that will be employed to ensure that the system satisfies the specified criteria. Verification method requirements are typically focused on the process of verifying requirements rather than the requirements themselves.

Examples of verification method requirements include specifying the use of testing, simulation, analysis, inspection, demonstration, or other verification techniques to validate a requirement.

Verification method requirements define how verification activities will be conducted, while verification requirements define what needs to be verified and the criteria for verification. Both types of requirements are essential for ensuring that the system meets its specified functional, performance, and other requirements, and they help establish a systematic approach to verifying system compliance throughout the development lifecycle.

Navigating these different requirements and combining them to optimize your system all fall under Systems Engineering Requirements Management.

Tip: Learn How to Plan your Verification and Validation Early in the Lifecycle. 

The Requirements Management Processes and Techniques

1. Gathering Requirements 

During the initial Elicitation phase, the requirements-gathering team embarks on a mission to collect vital information from stakeholders regarding their needs, aspirations, and limitations.

The first step involves pinpointing the stakeholders, which include project managers, developers, marketing personnel, quality assurance teams, and notably, the end-users of the system or product in question. Engaging in thorough interviews with these stakeholders allows the team to delve into their unique requirements, concerns, and expectations.

It's not uncommon for stakeholders to present a preliminary list of requirements at the project's outset. Nevertheless, conducting formal interviews post a preliminary quality evaluation of these requirements is crucial. This approach aids in clarifying any misunderstandings and addressing any issues related to the quality of the requirements.

Employing group studies and surveys emerges as a powerful strategy to solicit input from the end users, who represent the most significant stakeholder group. It's essential to formulate questions that are clear, succinct, and zero in on particular project facets to elicit insightful responses.

Another insightful method for requirement extraction is to model the current system or product, a process typically dubbed as the 'As-Is' or baseline analysis. This technique allows the team to distill the system into its core functionalities and evaluate performance metrics, such as the end-to-end execution time or the mean time to failure (MTTF). These gleaned functional and performance metrics set the benchmark for the minimum requirements that a new system or service must fulfill.

Importantly, the new system or product, alongside the existing model, should remain design agnostic. This hallmark of a robust requirement implies that the features of current or envisioned systems are abstracted to a higher level, ensuring the focus remains on the functional essence.

Related Articles:

9 Methods for Requirements Gathering

Producing Requirements Through System Thinking

Stakeholders Roles in Requirements Management

2. Documenting Requirements

Now that you’ve gathered a list of requirements, you will want to start the documentation process. Record gathered requirements in a structured format. This could be in the form of textual descriptions, diagrams, use cases, user stories, or other documentation formats that suit the project's needs.

Use a Tool

Depending on the scale and complexity of the product, process, or system, you will want to find the appropriate tool to help you with documentation. Further down, this guide discusses different tools. Innoslate has a hybrid user experience between a word-processing tool and a spreadsheet editor. It allows you to document traceability and collaborate with large teams.

You can also create relationships between requirements, diagrams, use cases, user stories, models, and more. Whichever tool you decide to use, recording requirements in a structured format, such as a requirements document, is essential as it serves as a reference for all stakeholders.

Choose a Template

You can use pre-built templates or develop and reuse your own templates. Innoslate offers two built-in requirement templates: CDC Functional Requirement and DAU Operational Requirement.

Add Rationales

Document the rationales for the requirements. In a column next to the requirement, ensure that the rationale is clearly defined as to why that requirement exists. Here’s an example of a rationale for the requirement: "The system shall encrypt all user passwords stored in the database using AES-256 encryption algorithm."

The rationale could be: "The requirement to encrypt user passwords using AES-256 encryption algorithm is essential for ensuring the security and confidentiality of user data. Storing passwords in plaintext poses a significant security risk, as it exposes sensitive information to unauthorized access in the event of a data breach. By encrypting passwords using a strong encryption algorithm like AES-256, we can protect user data from being compromised, even if the database is accessed by unauthorized parties. This requirement aligns with industry best practices for safeguarding sensitive information and helps mitigate the risk of unauthorized access and data theft."

Add Relationships

Before moving to analyzing requirements, start documenting the relationships. For example, you could create a relationship between the above requirement and the verification method requirement: "The system shall undergo penetration testing conducted by a certified security expert to verify compliance with the requirement to encrypt all user passwords stored in the database using the AES-256 encryption algorithm."

Many tools will also automatically create the parent-child relationship for you as you create the hierarchy.

3. Analyzing Requirements

Once the documentation is complete, it’s time to start analyzing the requirements.

Analyze for Quality  -  First, analyze the requirements document for quality. You'll want to look for the following attributes in each requirement to ensure high project performance. The following attributes and descriptions are from the INCOSE Guide to Writing Requirements. 

Below is an example of the feedback received from the Quality Check tool in the requirements software Innoslate. You can use a tool like Innoslate to quickly grade the quality of your requirements with natural language processing (a form of AI technology). The Quality Check checks for attributes that are clear, complete, consistent, designed, traceable, and verifiable.

If you are not using a quality checking tool carefully go through each requirement and be sure to document whether a requirement meets the quality attribute's description above. 

The example uses the requirement description, "The FireSAT system shall detect potentially dangerous wildfires (defined to be greater than 150m in any linear dimension) with a confidence interval of 95%." The "R" followed by a number is linked to the rules set in the INCOSE Guide to Writing Requirements. Take a look in the example below to see what errors the Quality Check tool found.

Example of Requirements Tool Quality Feedback

The Conforming Attribute

Here are the industry standards recognized verbs associated with the Conforming attribute, designed to enhance the specificity and clarity of your requirements:

• "Shall" is employed for binding requirements that must be verified, with a corresponding verification method. It is usually applied to functional requirements.
• "Must" indicates certain quality and performance criteria that need to be verified and accompanied by a method of verification. It is usually applied to non-functional requirements.
• "Will" is used to express statements of fact, purposes, or expected events, and is not binding.
• "Should" represents attributes, goals, or best practices that the system design must consider (informational), but it is not binding.
• "Need" represents a high-level desire or expectation of stakeholders that guides the development of the system. Needs are often expressed broadly and form the basis from which detailed lower-level requirements are derived.

"Shall" and "must" are often used to split the functional and non-functional requirements, respectively. This allows for clear differentiation and consistency. However, you can use "will," "need," and "should" when applicable, as they are not restricted to being functional or non-functional requirements. Ensure each requirement has only one provision or declaration of purpose (such as shall) to avoid conjunction requirements. The Quality Check feature will also help ensure that these verbs are used to conform to industry-standards.

4. Manage Change

Change management is a structured approach used to transition individuals, teams, and organizations from a current state to a desired future state. 

At this point, you should have high-quality requirements documented and properly traced. Next, you need to manage revisions and changes to the documents and individual requirements. It’s important to understand the impact those changes will make. 

Baseline and Version Control

The first step you will take is to baseline the requirements documents. Ensure the tool you are using has version control set at the entity level of each requirement so that it’s possible to revert changes without changing the entire document.

Innoslate offers a History feature that tracks each change to a requirement or any entity in the database. Baseline changes during different review phases so you may have a review phase and you allow all the comments and change requests to come through. Baseline the document before editing and accepting changes to preserve the different phases and easily revert.

Impact Analysis

Next, you need to understand the impact that changes will make. Creating a spider diagram will allow you to do this easily. Innoslate auto-generates a spider diagram. This allows you to see what the requirement is related to and answer questions such as, “Will changing this requirement change the way you perform an action later,” or, “Will it change the way you verify the requirement?” 

Understanding all the interconnected relationships of your requirements is the key to successful requirements management.

Change Requests

Change requests allow a user to make suggested edits to requirements documents. This is similar to track changes in Microsoft Word. The requirement engineers can review and approve which suggested edits will make it to the next baseline.

Alternatively, users can simply leave comments with suggestions or concerns. Set a due date for when all requests need to be made. Ensure that the document has been baselined before approving change requests and completing suggested changes. 

Branch and Fork

Branching and forking are powerful techniques in requirements management that can significantly enhance the flexibility, collaboration, and traceability of the development process. Innoslate allows you to branch and fork your projects to help manage change and complexity in its tool Project Version Control.

Related Article: 6 Reasons You Need Branching And Forking in Requirements Management

Approvals

Approvals are crucial in change management for ensuring accountability, maintaining quality, managing risks, aligning stakeholders, facilitating communication, meeting regulatory requirements, and managing resources. You can complete approvals through Innoslate’s Workflows, which locks documents, provides notification of approval, and allows users to edit.

Baselining, assessing impact, change requests, version control are all important parts of change management.  Controlling changes to requirements throughout the project/product lifecycle is a critical step in the requirements management process.

5. Traceability

Establishing and maintaining traceability between requirements and other project areas. This could be through design documents, test cases, the Requirements Traceability Matrix (RTM), and more to ensure alignment and transparency.

An RTM is especially helpful in tracking the relationship between requirements and other project elements such as design, implementation, and testing. It ensures that every requirement is accounted for and has been addressed in the final product. By maintaining an RTM, project managers can easily identify the impact of changes to requirements, verify that all requirements have been met, and ensure comprehensive testing.

Traceability matrices are an important aspect of requirements management. Innoslate's Requirements Traceability Matrix provides an interactive matrix view that allows you to visually represent relationships between groups of entities. It also uses AI to find missing and improper relationships. 

Learn More About Generating and Analyzing Traceability Matrices with AI.

6. Verification and Validation

Verification and Validation (V&V) is confirming that requirements are complete, consistent, and aligned with stakeholder needs using techniques such as reviews, walkthroughs, and validation tests.

Effective Requirements Management ensures that your system delivers the intended outcomes within schedule and budget constraints while meeting stakeholder expectations. V&V helps minimize the risk of scope creep, conflicting requirements, and misunderstandings among team members.

Verification Methods

Depending on the system or product, there are many different methods of verification. Below are several that can be used across a variety of industries. 

1. Modeling and Simulation

Test your models as you are building them to ensure accuracy. Tools like Innoslate have built-in discrete event simulation to ensure proper execution. 

Define Objectives

Determine the key performance indicators (KPIs) and metrics for evaluation. Innoslate's AI Quality Checker will ensure that your requirements are measurable. 

Develop Models

You can start by developing the functional and physical models for the proposed system or product. If you already created an As-Is model, then you have a great place to start with your modeling efforts.

Run Simulations

Execute simulations in Innoslate to evaluate system performance under various scenarios. Test your models as you are building them to ensure accuracy throughout the lifecycle. This makes it even easier to pinpoint exact issues.

Tools like Innoslate have built-in discrete event simulation to ensure proper execution. Perform sensitivity analysis to understand the impact of different variables on the system.

Analyze Results

Now it's time to compare simulation results against the predefined requirements and KPIs. Identify discrepancies or areas where the system does not meet requirements.

Report Findings

Document the simulation process, results, and corrective actions. In the Test Center, you can easily create new tests. Use Innoslate's reporting features to present findings to stakeholders.

Baseline the Models

Before you start to make changes based on the results of the simulation, make sure to baseline the models. Compilations View makes it simple to baseline a model.

2. Software Testing - Selenium

For this example, we are going to use a free and open-source automated testing software, Selenium, to ensure that the specified requirements are met. Innoslate integrates with Selenium and can be used to document the results as shown below.

1. Test Planning:

   • Define the scope and objectives of Selenium testing within Innoslate.
   • Identify test cases based on software requirements and user stories documented in Innoslate.

2. Set Up Test Environment:

   • Configure the testing environment, including web browsers and test data.
   • Install and set up Selenium WebDriver and other necessary tools.

3. Develop Test Scripts:

   • Write automated test scripts using programming languages supported by Selenium.
   • Ensure scripts cover all identified test cases and include validation checks, referencing Innoslate for requirements traceability.

4. Execute Tests:

   • Run automated test scripts and link results back to Innoslate.
   • Perform cross-browser and cross-device tests to ensure compatibility.

5. Analyze Results:

   • Review test execution reports to identify failed test cases.
   • Debug and fix issues, re-running tests as necessary, and updating Innoslate with results.

6. Report Findings:

   • Document test results, including pass/fail status and issues encountered in Innoslate.
   • Use Innoslate’s dashboard to provide detailed reports to the development team and stakeholders.

3. Reviews and Inspections

Execute comprehensive evaluations of your project's documents, software code, and additional elements utilizing the robust collaboration and documentation functionalities of Innoslate.

Planning for Reviews

Pinpoint the specific items needing examination (such as requirements documentation, design outlines, or code snippets). You can easily do this within Innoslate's documentation tools and labeling features. Organize review meetings and handpick participants leveraging Innoslate's advanced collaborative utilities.

Preparing for Reviews

Efficiently allocate the items to be reviewed by your team. In Innoslate, you could assign a task to that requirement to a team member. The team member will receive an email notification. Supply them with detailed checklists and guidelines to ensure an exhaustive and effective review process. This can also be accomplished through project management features in Innoslate such as Kanban Boards and Gantt Charts.

Adding a Task to a Requirement in Innoslate.

Executing Reviews

Facilitate review sessions, engaging in a methodical scrutiny of each item with the aid of Innoslate’s specialized review tools. Log any discovered defects, concerns, or improvement suggestions directly into Innoslate.

Analysis of Review Outcomes

Gather and sort the insights garnered from the review sessions in Innoslate. Evaluate the gravity and potential impact of each identified issue, ensuring nothing slips through the cracks.

Reporting on Findings

Chronicle the entire review cycle and its outcomes within Innoslate. Communicate these insights with your project team, initiating necessary corrective measures and monitoring modifications within Innoslate for seamless project progression.

4. Prototyping

Leverage Innoslate for managing prototyping efforts and capturing feedback.

1. Clarify Goals:

   • Identify the precise requirements and capabilities that the prototyping phase aims to validate in Innoslate.

   • Determine the scope and intricacy of each prototype, recording every detail with precision in Innoslate for full transparency

2. Develop Prototypes:

   • Leverage cutting-edge rapid development methodologies to breathe life into your prototypes. You can use CAD/CAM tools and 3d printers to create working prototypes.

   • Utilize Innoslate to effortlessly monitor and refine the progression and adjustments of each prototype version.

   • Store and view CAD/CAM files in Innoslate and autogenerate asset hierarchy diagrams for better impact analysis.

3. Evaluate Prototypes:

   • Perform thorough functional and usability assessments of your prototypes, gathering insightful feedback.

   • Track test outcomes, user surveys, and feedback scores in your requirements tool to ensure traceability to the requirements and the verification process.

4. Assess Feedback:

   • Analyze the received feedback and continue to test data to pinpoint strengths and potential areas for improvement.

   • Verify whether the prototype meets the requirements and document the test results in the Test Center.

5. Synthesize and Share Insights:

   • Systematically document the entire prototyping journey, from conception to conclusion, within Innoslate.

   • In Documents View, create a test plan from the test plan templates.

   • Develop a functional model of the test plan or verification process with either the action diagram or the activity diagram.

   • Share these critical insights with your project team, ensuring the project plan and specifications in Innoslate are updated to reflect the latest evolutions.