Transcript G W-Part5-Greatly Improving the Odds of Success

EXPLORING REQUIREMENTS –
QUALITY BEFORE DESIGN
Gause & Weinberg - PART V – Greatly
Improving the Odds of Success
1
Steps to ensure success
 Assess ambiguity in requirements
 Convene meetings to resolve issues
 Evaluate - measure satisfaction at each stage
 Test using test cases – open up the black box
 Use existing products as guides
 Get agreements in decisions
 End the requirements process
Ambiguity
 Measure Ambiguity – the ambiguity poll
 Analyze the ambiguity results from the ambiguity poll
 Diversity or the range of interpretations
 Clustering of the interpretations
 Investigate the sources of ambiguity
 sampling
 problem statement
 design process
 final product
 Arrive at resolutions
Technical Review (TR)
 What is it – a tool to assess sufficiency and reliability of
requirements
 Why needed - To discover omissions / errors /
misinterpretations
 Members - informal (internal: group); formal (external entities)
 Result - Review reports
 Types of TRs
Measuring Satisfaction
Measure - frequently at each stage
Thru surveys - use questionnaires with Likert scales
(7-point response scale: e.g., strongly disagree…
strongly agree)
Prototypes
Test cases
Exploring the black box of requirements
Successfully decomposing the complexity and
fuzziness thru test cases (iterative)
Steps:
Writing the test case
Administering the test case
Interpreting the results of the test case
Using Existing Products as Guides
Use existing products as a basis for comparisons
and gap analyses
More as a guide rather than a rigid norm
Distinguishing between features and functions in the
comparisons (prioritizing and categorizing)
Making agreements
Sources of decisions in projects
Choices – conscious decisions
Assumptions – decisions by default
• Turnpike effect / parking lot effect – most important
Impositions – decisions enforced by external sources
Try to convert assumptions to conscious decisions
since this is the trickiest
Try to get an understanding and agreement about all
decisions, esp. assumptions
Ending
Is there an end to the requirements process?
Challenges
Transient environment
Inability to freeze requirements
Renegotiation could become a Pandora’s box
However, the designer needs to identify an end for
practicality