Assessing Requirements Quality in Iterative Development 1

How Does One Go about Achieving Quality?  The very nature of the thing we produce, source code, models, and other artifacts, is intangible.  We must assure that the thing produced has the requisite quality to meet the needs of the users and extended stakeholders.  REQUIREMENTS QUALITY DRIVES SYSTEM QUALITY. 2

Software Project Quality  “Quality is conformance to requirements”  “Quality is achieved when the software is ‘good enough’”  “Quality is ultimately situational and objective”  “Quality is the characteristic of having demonstrated the achievement of producing a product that meets or exceeds agreed-upon requirements – as measured by agreed-upon measures and criteria – and that is produced by an agreed-upon process” [Rational Software Corporation 2002] 3

Software Project Quality (Cont’d)  Quality is a multidimensional concept that address two primary dimensions:  The end result of the application itself  The business impact on the producer and consumer  What we have studied in this course is how to effectively manage requirements to help the development team assure that the product or system being developed meets or exceeds agreed-on requirements and to apply an agreed-on process to help assure that those results are achieved. 4

Assessing Quality in Iterative Development  When we complete the delivery of an iteration we can ask the following questions: “Does it do what we said it would do?” “Does is appear to meet the requirements as we know them at this time?” “Did we do it about when we said we would?” Now that you can see a bit of this thing, is this what you really wanted? Is this what you really meant?”  We can look at the artifacts of the process and inspect them for quality as well. These artifacts demonstrate that the process is being followed as well. 5

Requirements Artifacts Sets Team SkillRequirements SetSet contents 1: Analyzing the ProblemProblem setProblem statement Root cause analysis Systems model List of design and development constraints List of actors Business use-case model 2: Understanding User and Stakeholder needs User needs setStructured interview, process, and results Understanding of users and user needs Requirements workshop process and results Preliminary list of prioritized features Storyboards, example use cases, etc. 3: Defining the SystemPreliminary system definition set Requirements organization Vision document Identification of initial use cases Empowerment of product manager/champion Definitions of commercial factors 6

Requirements Artifacts Sets (Cont’d) Team SkillRequirements SetSet contents 4: Managing ScopeBaseline setPrioritization and estimation of features Requirements baseline Recognition and communication of achievable scope Agreed-on expectations 5: Refining the System Definition Refined system definition setUse-case model(s) Use-case specifications Supplementary specification(s) Ambiguity and specificity considerations Technical methods (if any) 6: Building the Right System System under construction set Transitioning method (from design to code) Test cases (derived and traceable from use cases) Requirements traceability Requirements change management process Requirements method 7

Performing the Assessment  We have already put in place an iterative process whereby the objective evidence of the iterations themselves are the primary quality measures.  We can apply secondary measures by assessing each of the requirements artifacts at each iteration, or at any iteration we choose, by looking at the various aspects of quality that each artifact should contain at that point in the development process. 8