A condition or capability needed by a user to solve a problem or achieve an objective.
A condition or capability that must be met or possessed by a system or system component to satisfy a contract, standard, specification, or other formally imposed document.
A documented representation of a condition or capability as in 1 or 2.
The activities related to working with software requirements can broadly be broken down into elicitation, analysis, specification, and management.
Elicitation
Elicitation is the gathering and discovery of requirements from stakeholders and other sources. A variety of techniques can be used such as joint application design sessions, interviews, document analysis, focus groups, etc. Elicitation is the first step of requirements development.
Analysis
Analysis is the logical breakdown that proceeds from elicitation. Analysis involves reaching a richer and more precise understanding of each requirement and representing sets of requirements in multiple, complementary ways.
Validation involves techniques to confirm that the correct set of requirements has been specified to build a solution that satisfies the project's business objectives.
Management
Requirements change during projects and there are often many of them. Management of this change becomes paramount to ensuring that the correct software is built for the stakeholders.
Taking into account that these activities may involve some artifacts such as observation reports, questionnaires, use cases, user stories; activities such as requirement workshops, brainstorming, mind mapping, role-playing; and even, prototyping; software products providing some or all of these capabilities can be used to help achieve these tasks. There is at least one author who advocates, explicitly, for mind mapping tools such as FreeMind; and, alternatively, for the use of specification by example tools such as Concordion. Additionally, the ideas and statements resulting from these activities may be gathered and organized with wikis and other collaboration tools such as Trello. The features actually implemented and standards compliance vary from product to product.
A Software Requirement Specification document might be created using a software tool as general as a word processor or an electronic spreadsheet; but, there are several specialized tools to carry out this activity. Some of these tools can import, edit, export and publish SRS documents. They may or not help the user to follow standards such as IEEE 2918-2011 to compose the requirements according to some structure. Likewise, the tool may or not use some standard to import or export requirements ; or, not allow these exchanges at all.
Tools for Requirements Document Verification
Tools of this kind verify if there are any errors in a requirements document according to some expected structure or standard.
Tools for Requirements Comparison
Tools of this kind compare two requirement sets according to some expected document structure and standard.
Tools for Requirements Merge and Update
Tools of this kind allow the merging and update of requirement documents.
Tools of this kind allow to trace requirements to other artifacts such as models and source code or, to previous ones such as business rules and constraints.
Model-based systems engineering is the formalised application of modelling to support system requirements, design, analysis, measurement, verification and validation activities beginning in the conceptual design phase and continuing throughout development and later lifecycle phases. It is also possible to take a model-based approach for some stages of the requirements engineering and, a more traditional one, for others. All kinds of combinations might be possible. The level of formality and complexity depends on the underlying methodology involved
Tools for general Requirements Engineering
Tools in this category may provide some mix of the capabilities mentioned previously and others such as requirement configuration management and collaboration. The features actually implemented and standards compliance vary from product to product. There are even more capable or general tools that support other stages and activities. They are classified as ALM tools.
