transforming how companies work with technology. requirements seminar
TRANSCRIPT
Transforming how companies work with technology.
Requirements Seminar
What is a Requirement?
Something that the product must do or a quality that the product must have
Things you should discover before starting to build your product
What is a Requirement? What the Stakeholder
Needs Wants Asks for Expects Can have
A set of specific criteria that a product must meet in order to be acceptable to the stakeholders
“Your customers are not buying a product. They’re buying your assurances that their expectations for that product will be met” - J Guaspari
What is a Stakeholder? People who have a vested interest in the
product – will somehow be affected by its use
People who have requirements for the product
Before you can identify all the requirements, you must identify all the stakeholders.
Include the list of stakeholders in your requirements specification.
Why do we need Requirements?
Define the product Define product quality Help control complex projects Help manage Stakeholder
expectations Improve compliance with: CMM,
ISO, IEEE, etc.
Capability Maturity Model (CMM)
Congress founded the Software Engineering Institute (SEI) at Carnegie-Mellon University in 1984 to improve the practice of software engineering.
First version of CMM published in 1989.
Mature = predictability is high,
risk is low
CMM (continued) Five levels of maturity
1. Initial (75% - 85%)
2. Repeatable (5% - 10%)
3. Defined (3% - 7%)
4. Managed (2% - 3%)
5. Optimized (> 2%) Each level defines Key Process
Areas (KPA) and key practices within each KPA.
CMM Level 2 Project-focused Formalize the planning and mgmt.
of individual projects. Six Key Process Areas (KPA)
1. Requirements mgmt.2. Software project planning3. Software project tracking4. Software quality assurance5. Software configuration mgmt.6. Subcontractor mgmt.
The Spirit of CMM Say what you do and do what you
say. For Level 2,
Repeat processes from project to project
Study the results Improve the process if necessary
Accumulate artifacts that substantiate the top bullet point.
Establish a Repeatable Process
Identify stakeholders Mine Define Refine Combine (requirements specification) Signoff Change control, reuse library
Identify Stakeholders Sponsor Current Users New Users Management Customers PMO Development team Legal Marketing
Government Industry Public Special interest
groups Existing IT
systems Production
support team ???
Mine for Requirements
Partners
Users
Analysts Business Plans Personal Goals
Domain ExpertsIndustry AnalystsSite VisitsCompetitive info
Problem Domain
Customers
Bug ReportsChange Requests
The Key Listen Re-state Do not stop until YOU have a clear
picture – YOU manage the expectations – YOU must have the vision.
Document your understanding Get signoff on your document
Requirements Should Address: Business impact Business need Impact on the organizational
processes Impact on the existing and
planned systems Business and technology strategies
Techniques for finding potential requirements
InterviewingJAD (Joint application development) Brainstorming Facilitated Sessions Prototyping Use Cases Usability Studies Document Gathering Inspection
More techniques for finding potential requirements
Surveys Business procedures and standards Data flow diagrams Client Liaison Data and process models Data dictionary definitions Existing code unit specifications Comments in existing code Reuse library
Stating Requirements Accurately
Essential Characteristics of Requirements Complete Unambiguous Consistent Verifiable Precise Detailed
Define Requirements - Requirement Attributes
Description Rationale Source Source date Unique identifier Requirement type Requirement sub-type Requirement level Priority Test Case
DescriptionUse consistent format
Verb - Modifier - Direct Object – (on condition)
Examples Capture (verb) customer (object modifier)
information (object). Calculate (verb) monthly interest (object
modifier) payments (object). Issue (verb) warning (object modifier) alert
(object) on error (condition).
Emphasize “what” not “how”.
Types of Requirements Functional requirements
What will the product do? What, not how
Non-functional requirements What qualities must the product
have? Constraints
What limitations exist regarding the way the product is produced?
Sources of Requirements
Client requirements Technical requirements Audit and control requirements Corporate standards Operational requirements Regulatory bodies
Additional Sources of Requirements
Manual and administrative requirements
Scheduling and performance requirements
Database requirements Security requirements Audit and control requirements
Refine Requirements Must pass quality check before
being added to requirements specification and database.
Must verify and validate. Decomposition
The Need for Quality Requirements
60% - 66% of errors originate with requirements and analysis activities.
45% of problems requiring maintenance are detected after completing acceptance tests.
The cost of fixing problems during final testing is 50-100% higher than during requirements specifications.
What Is Quality? The level with which a product
meets all its defined requirements; Therefore,
You can’t measure quality without fully defining the requirements
Each requirement should be measurable/testable.
Verify and Validate Requirements validation and
verification are the joint responsibility of the test analyst and the client/end user.
Validating requirements before coding begins minimizes costly design and code modification.
Acceptance and Integration tests begin by validating that the requirements meet user’s expectations and are testable.
Validating requirements
Requirement
Validate sign-on
Validate password
Invalid term ident
Password/ Signon error
Validate Main Menu
Re-enter O, X, M, R
Validate Customer #
Customer # Required
Field entry too long
Customer ___ not found
Test Case1 2 3 4 5 6x
x
x
x
x
x
x
x
x
x
Decomposition
Identifying requirements in a top-down fashion
Process of refining requirements Requirements are categorized at three
major levels of detail: High Intermediate Detail
Decomposition High Level Requirements
Broadest category of functions Major business processes Operations manuals, user manuals,
procedures External systems interfaces System controls
Special requirements Volume/Stress requirements Backup/Recovery requirements Performance requirements
Used to define and validate the build structure
Decomposition Intermediate Level Requirements
Components of intermediate level requirements may include:
Sequences of actions to be taken Information to be displayed or reported Error routines and messages Interfaces to other system modules Transaction descriptions
Edit, update, etc. Used to define and validate test runs
Decomposition Detail Level Requirements
Specific steps in application processing, such as:
Action steps Field definitions Edit criteria Calculations Error messages
Used to develop test cases
Validating Detailed Requirements
Requirements Decomposition Complete when each defined requirement
can be validated by one or a small number of test cases
If you can not develop a test case for a requirement, you need to dig further
If you are having difficulty developing test cases, other design activities focusing on the specific function in question should be stopped until requirements can be clarified or augmented
“BAD” words Watch Out For
Words Like: Often Always Sometimes Never Usually Fast User friendly Timely
Most of the time Quickly Could Might/May Good Satisfactory
Be careful of: Unintended implications of
certainty always, never
Passive tense phrases the counter is set
Pronouns for which references are not clear
Unclear comparatives earlier easiest most valuable
And… Unqualified attributes
flexible, efficient, organized
Ambiguous words quickly, adjacent
Contractually troublesome phrases where applicable
Combine and Review Produce requirements specification Should include
Product purpose List of Stakeholders and their roles Constraints Assumptions Functional requirements Non-functional requirements
Consistency check, missing requirements
Obtain Signoff Client understands the system IT understands the requirements Go directly to change control
Change Control No requirements are changed, added or
deleted without going through the change control process.
A change request form is filled out specifying the requested change, the source and why the request is being made.
The change is analyzed and the potential impact is added to the form.
Change control board reviews and sponsor signs off.
Reuse Library Collection of artifacts Enables repeatability Saves time, effort, re-work Many constraints will likely be the
same Stakeholder list will likely be similar Use items as needed
Lessons Learned What techniques were used to
identify requirements? How well did they work? Can they be improved upon? Document
Discussion
Contact Info:
Bill Ax – Account Executive
608-233-8201
Mike Lawler – SQM Practice Director
630-919-2912