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?
- 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).
For more information I highly recommend this post at the Gemba Walkabout: http://gembawalkabout.tumblr.com/post/34257410679/understand-variation-the-forgotten-principle.
Sep 14 2023
Deming’s 14 Points (Point #13): “Institute a vigorous program of education and self-improvement for everyone.”
As I have said many times: “multi-million dollar projects shops don’t just run themselves”. You need a dedicated team of staff to support project managers and project analysts in order for them to really “knock it out of the park”. We achieve this at Coast Capital Savings in our Enterprise Project Management Office (EPMO) Centre of Excellence (CoE) who are dedicated to supporting the day to day delivery by the project teams. This include education, training, and coaching to ensure all audit requirements/benefits capabilities are met and unnecessary delays and cost overruns are avoided.
The question I have asked to our project teams is…Does the existence of a “vigorous program of education and self-improvement” make a difference in your skill/ability to deliver projects (knowing that ultimate success requires good change/adoption support and operational commitment to benefits realization)?
By Craig "hachiroku" Mercer • Quality (Systems Thinking) •