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?
Contact Information
◦ Email
david.whalen@comcast.net
◦ Instant Messenger
MSN: david.whalen@comcast.net
Yahoo: dave_whalen14@yahoo.com
More Stuff
◦ www.stickyminds.com
◦ Search on “whalen”