Practical
Story Sizing
Brett Maytom
Senior Consultant, Readify
Vic .NET – 13 Aug 2011
Talk Backlog
 What
is size
 Relative Size
 Sizing Scales
 Velocity
 Story Size versus Task Sizing
 Running Sizing Meetings
 Questions
What is size?
 Unit
of measure for work
Why Relative Sizing
 Your
Time IS NOT My Time
Size does not …
 indicate
time
 Indicate skill
 include risk
 change over time
 Increase\decrease with proficiency
Relative
It’s relative
Sizing Scales
 Fibonacci
1 2 3 5 8 13 21 34
 Modified
Fibonacci
1 2 3 5 8 13 20 50 100
 Binary
1 2 4 8 16 32 64 128
 T-Shirt
S
M
L
XL
Other Symbols
0
(Zero)
“Too small and not worth sizing”
?
“I have no idea what you are talking about”
∞
(Infinity)
“This is way too big”
Velocity
 Rate
of work of team
“Team can complete X story points per sprint”
 Not
individual
 Full team
including BA, QA, Dev., Test, Architect, Scrum
Master
 Improves
with time
Story Sizing
 Uses
a relative sizing scale
 Not done at iteration planning
 Used for Release Planning
𝐵𝑎𝑐𝑘𝑙𝑜𝑔 𝑆𝑖𝑧𝑒
# 𝑆𝑝𝑟𝑖𝑛𝑡𝑠 =
𝑉𝑎𝑙𝑜𝑐𝑖𝑡𝑦
Stories and Tasks
Task Sizing
 Tasks
defined in sprint planning
 Sized in hours
 Updated daily with remaining hours
 Used for sprint burndown
 Cross-check against Story Size using
current velocity
Sizing in multi-team
 Consistent
story size critical
 Large scope differences
 Clear benchmarks
 Central team
How to play Planning Poker
 Product




owner presents a story
Team clarify by asking questions
“1 … 2 … 3 … show”
Smallest and largest values explain
Repeat until consensus reached
Spikes
 Totally
new technology
 Never done before
 Have no idea how to size work
 Time-boxed
to a few days
Acid Test
A story sized in
the first sprint
should have the
same size in
later sprints
Practical Tips
 Use
relative sizes for stories
 Do not factor in effort, risk and time
 Build a list of benchmark stories
 Continually inspect that “time” is not
introduced story
 Differentiate between Task and Story sizes
 Your Time IS NOT My Time
Thank you
Brett Maytom
brett.maytom@readify.net
@brettmaytom
http://brett.maytom.net