Craig Mercer's thoughts on the nature of variation and "crossing the streams" of Project Management with Benefits Realization Management, Organizational Change Management and Process Improvement (Lean Design).
Don’t attribute (good or bad) to people that which should be attributed to the system.
What is variation?
a change or difference in condition, amount, or level, typically with certain limits
Impact of Variation
Variation results in:
adverse patient safety events
reduced job satisfaction
loss of productivity
loss of revenue
…so we should try and reduce variation.
Types of Variation
There are two types of variation and they require different approaches to remove them
Common-cause variation is characterised by:
Phenomena constantly active within the system;
Variation predictable probabilistically;
Irregular variation within an historical experience base; and
Lack of significance in individual high or low values.
Special-cause variation is characterised by:
New, unanticipated, emergent or previously neglected phenomena within the system;
Variation inherently unpredictable, even probabilistically;
Variation outside the historical experience base; and
Evidence of some inherent change in the system or our knowledge of it.
Determining Variation Types
Hey Craig! How can we understand what kind of variation we are dealing with?
Common Cause Examples
Lack of clearly defined standard operating procedures
Inappropriate procedures
Normal wear and tear
Variability in settings
Computer response time
Poor design
Poor maintenance of machines
Poor working conditions, e.g. lighting, noise, dirt, temperature, ventilation
Substandard raw materials
Ambient temperature and humidity
Special Cause
Operator falls asleep
Machine malfunction
Computer crashes
Poor batch of raw material
Power surges
Broken part
Abnormal traffic (click-fraud) on web ads
Extremely long lab testing turnover time due to switching to new computer system
Operator absent
Responding to Variation
Response to common cause variation is incremental and requires data (measurement)
Response to special cause tends to be knee-jerk and expensive.
So why do we care Craig?
We should care because more often than not the wrong type of variation is suspected and then the wrong response is applied (tampering), which is not only more expensive but it negatively impacts the staff working within the system.
For example, what was the reaction to the 9/11 attacks in the United States? They spent billions of dollars tampering with the system (a common cause response) that ultimately has not increased safety because it was not the source of the variation in the first place. The nature of special cause variation is that it never happens the same way twice (which is why the terrorists opted for shoe explosives instead of box cutters the next time around).
Apr 11 2015
Thoughts on Variation
Don’t attribute (good or bad) to people that which should be attributed to the system.
What is variation?
Impact of Variation
Variation results in:
Types of Variation
There are two types of variation and they require different approaches to remove them
Common-cause variation is characterised by:
Special-cause variation is characterised by:
Determining Variation Types
Hey Craig! How can we understand what kind of variation we are dealing with?
Common Cause Examples
Special Cause
Responding to Variation
So why do we care Craig?
We should care because more often than not the wrong type of variation is suspected and then the wrong response is applied (tampering), which is not only more expensive but it negatively impacts the staff working within the system.
For example, what was the reaction to the 9/11 attacks in the United States? They spent billions of dollars tampering with the system (a common cause response) that ultimately has not increased safety because it was not the source of the variation in the first place. The nature of special cause variation is that it never happens the same way twice (which is why the terrorists opted for shoe explosives instead of box cutters the next time around).
For more information I highly recommend this post at the Gemba Walkabout: http://gembawalkabout.tumblr.com/post/34257410679/understand-variation-the-forgotten-principle.
By Craig "hachiroku" Mercer • Quality (Systems Thinking), Variation •