Transcript Defect Priority Matrix - Software Quality Association of
The “Matrix”
Dave Whalen Whalen Technologies
Overview
Quick Review: Triage Severity vs. Priority What is the “Matrix”?
Why do we need the Matrix?
Using the Matrix
Quick Review – Triage
French – “sorting” A system used by software development teams to ration limited technical resources when the number of defects needing resolution exceeds the resources available to correct and verify them so as to resolve the greatest number of defects possible. (My definition)
Severity vs. Priority
Often use interchangeably NOT THE SAME THING!
Severity – defines the impact the defect has on the customer and likelihood of occurrence ◦ Obscure Fatal System Error vs. Spelling Error Priority – determines the order in which defects will be fixed/resolved and retested ◦ Obscure Fatal System Error vs. Spelling Error
Determining Severity & Priority
Initially defined during defect discovery Validated during “Triage” Ordinal data ◦ Not numeric, relative ranking only ◦ Highly subjective!
How many levels?
◦ Between 4 & 5 ◦ Odd vs. Even ◦ Order (1-4, 4-1)
Priority
Defects should be resolved based on Priority NOT Severity!
Answers 2 Questions: ◦ What do we fix?
◦ When do we fix it?
Based on: ◦ Impact on the Customer (Impact or Severity) ◦ Resolution Difficulty (Difficulty) Time Resources
The “Matrix”
Visual tool or … “Mental” process Assists in evaluating and prioritizing defect resolution Ranking 2 Factors: ◦ ◦ Difficulty (x-axis) Severity/Impact (y axis)
The “Matrix” – What To Fix?
◦ ◦ Assess defects in terms of: Difficulty – 4 levels Severity/Impact – 4 levels Plot results ◦ ◦ 16 possible points Note: no fence-sitting
The “Matrix” – What To Fix?
Assign Priority based on Quadrant (Q Score) ◦ ◦ ◦ Q-Score = Priority ◦ QI = Priority 1 QII = Priority 2 QIII = Priority 3 QIV = Priority 4 Additional ranking within a Quadrant
The “Matrix” – When To Fix It?
QI - Priority 1 ◦ Low Difficulty, High Impact ◦ Fix it Now!
QII – Priority 2 ◦ High Difficulty, High Impact, ◦ Prior to next build
The “Matrix” – When To Fix It?
QIII – Priority 3 ◦ Low Difficulty, Low Impact ◦ Defer to next minor release (dot release – 1.1, 1.2, 1.3, etc.) QIV – Priority 4 ◦ Low Difficulty, High Impact ◦ Defer to next major release (2.0, 3.0, 4.0, etc.)
Summary
Quick Review: Triage Severity vs. Priority What is the “Matrix”?
Why do we need the Matrix?
Using the Matrix
Questions?
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