The Virus of Variability
(Gurus, Graphs
and Delay Attribution)
Richard Capper
The Universal Improvement Company
What I am going to cover
(1) Gurus
Dr. W. Edwards Deming,
Walter Shewhart, Don Wheeler
(2) Graphs
Run Charts, Histograms and Pareto
Charts
(3) Delay Attribution
via Ishikawa Diagrams
Gurus - Dr. W. Edwards Deming
“If I had to reduce my message
to management to just a few words,
I’d say it all had to do
with reducing variation”
Key points about Dr. Deming:
(1) Japan
(2) Japanese railways
(3) Current fads such a Lean and Six
Sigma are based on his work
Gurus - Walter Shewhart
(1) Dr. Deming was his student
(2) The inventor of Statistical Process
Control
(3) Discovered that there are two
distinct types of variation - common
and special. Common is always
present in the process, special is
‘unusual’. The two can be separated
out by using Control Charts.
Gurus - Don Wheeler
(1) Still going strong!
(2) Uses the term ‘Process Capability
Chart’ instead of Control Chart.
(3) An early step in improvement (or
even contract management) is
establishing what the current process
is capable of. Regrettably, targets
make no difference.
Graphs - Run Charts
(1)
The starting place for understanding how
your processes are behaving and therefore
what they are capable of
(2)
Typical Run Charts in performance
management:
Minutes late at destination
Number of cancellations per day
(3)
Adding Control Limits at three Standard
Deviations from the mean turns a Run Chart
into a Control Chart and separates special
from common causes
Graphs - Histograms
(1)
Also known as Frequency Distributions as they
show how frequently a particular value on a
Run Chart occurs
(2)
Vary by location, shape and spread
(3)
Generally underused in Performance
Management
Graphs - Pareto Charts
(1)
Answers the questions ‘why late?’ (Run Chart =
how late?) and ‘why cancelled?’ (Run Chart =
how many cancelled?)
(2)
The graph is based on an important principle
adopted from the work of Vilfredo Pareto by Dr.
Joseph Juran. This is commonly known as the 8020 rule.
(3)
Helps to distinguish between the ‘Vital Few’ and
the ‘Useful Many’ (formerly ‘Trivial Many’).
(4)
Main application in Performance Management
is deciding what to work on.
A ‘so what?’ moment
(1)
You should have a variety of Run Charts
(preferably Control Charts), Histograms and
Pareto Charts at your disposal if you want to
improve performance.
(2)
Pareto Charts require data about ‘why
late?’ to be available as well as ‘how late?’
‘Why late?’ is trickier to collect.
(3)
And philosophically, understanding process
capability comes before improvement.
Setting unrealistic targets just drives odd
behaviours.
Ishikawa Diagrams
(1)
Also known as Cause-and-Effect Diagrams
(2)
Invented by Professor Kaoru Ishikawa in 1943
to investigate impurities in steel at the
Kawasaki Steel Works
M e th o d s
P e o p le
(3)
E q u ip m e n t
E n v ir o n m e n t
M a te r ia ls
‘Ishikawa thinking’ can help us to categorise
causes of delay and, once we have
categorised them, they can be paretoed
What needs to be in place 1
Processes
•
A sensible performance regime between
Authority/commissioner and operators
•
A (joint) Performance Improvement Process
driven by senior managers who understand
it is their role to drive big cross-functional
projects
•
A delay attribution process - delays are
codified in real-time and allocated to the
Responsible Manager (infrastructure, fleet,
operations, external factors etc)
•
Performance data informs the planning
process
Other industries
The same principles apply:
Housing:
(1)
Rent arrears
Why?
(2)
Repairs
Why?/What?
(3)
Voids
Why?
Delay Attribution
(1)
This is the jargon term for attributing a delay
to a cause.
(2)
The best Delay Attribution has a well
thought-through hierarchy based on
Ishikawa thinking - main bones and subbones - and a codification structure that is
understood and applied with consistency.
(3)
The ‘main bones’ in heavy rail will typically
be rolling stock, infrastructure, operations,
etc.
Delay Attribution
(1)
We have been working with Queensland
Rail and TransLink to produce a Delay
Attribution hierarchy suitable for driving
improvement.
(2)
We have been looking for anything similar in
bus (help please).
(3)
In the UK there is a Delay Attribution Board
and a Delay Attribution Guide (on-line,
google it).
Delay Attribution
common pitfalls
(1)
Force majeure thinking:
Not my fault
Contractually exempt
Too difficult - acts of God
(back to Japan for a contrast)
(2)
Those minutes aren’t mine, they’re yours
(3)
Inconsistency between delay attributors
(round in a big circle to reducing variation)
(4)
David might have some more
Delay Attribution
Quote from the DAG
For all parties to work together to
achieve the core objective of delay
attribution - to accurately identify the
prime cause of delay to train services for
improvement purposes.
Reality = what the customers
experience
•
My last boss
•
Plan vs. Actual
(everything else is irrelevant in the
eyes of the customer)
Reggie Perrin