This talk teaches you about queues and how the choices we make to manage them can make or break your predictability. This is a primer to queueing theory without statistics. It ends with suggestions on how to monitor indicators of predictability.
2. Adjective
Expected, especially on the
basis of previous or known
behavior
[good or bad!]
Predictable
[pri-dik-tuh-buh l]
@everydaykanban
USUALLY
GREAT!
USUALLY
HORRIBLE!
USUALLY
________!
3. How many telephone
lines are needed to avoid
blocked calls given
§ Random arrivals
§ Random durations
Pulling answers
from randomness
@everydaykanban
4. The mathematical study of
waiting lines, or queues.
Can quantify relationships
between queue size, capacity
utilization and cycle times
Queueing Theory was the solution
@everydaykanban
capacity utilization (rho)
Queue size (N)
8. Mo’ queue, Mo’ problems
@everydaykanban
§ Longer average
cycle times
§ Wider range of
cycle times
§ More mgmt
overhead
§ Reduced
motivation &
quality
10. As interpreted by
Don Reinertsen
Aesop’s Fable:
The Tortoise
and the Hare
@everydaykanban
11. Predictability ≠ fastest
UNLESS
you can consistently
be that fast.
To become more
predictable…USUALLY
DONE IN
2 to 200
DAYS!
@everydaykanban
USUALLY
DONE IN
25 to 35
DAYS!
reduce the range of probable
outcomes.
20. @everydaykanban
Cycle time ranges: Lagging indicator
NovOctoberSeptemberAugustJuly
Good clustering
Can we reduce the outliers?
95%: 45 days or less
23. @everydaykanban
Queue Size: predicting predictability issues
Bigger queues lead to
longer cycle times,
less predictability
Smaller queues lead
to shorter cycle times,
more predictability
Work-In-Process
(hidden queues?)
Queued work
9
20
10
2
24. @everydaykanban
• Remember, you have control over predictability!
• Get baseline measures of queue size/cycle times.
• Make informed choices about handling queues.
• Monitor queues to anticipate and correct issues
before they negatively impact cycle times.
26. www.leankit.com
To receive a copy of:
• The slide deck for today’s presentation
• LeanKit’s 1st Annual Lean Business report
Send an email to: julia@leankit.com
Subject: DOES16