Archive | April 2015

Three thoughs for today


Measuring work is not enough. You have to measure value.

Bill Waddell

We forget this too often!

Scrap doesn’t come for free, we pay someone to make it.

Edwards Deming

So sad, so true.

A good decision is based on knowledge and not on numbers.


And that’s why “a group of experts who solve your problems for you” is a wrong Lean approach

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Root cause analysis Rule #2


Another classic mistake in Root Cause Analysis is to believe that correlation implies causation. It does not. In simple words, the observation of 2 events happening almost at the same time or 2 variables going up and down together is not enough to prove that one is the cause of the other. This is a bit tricky because some statistical tests (e.g. regression analysis) used in Lean or 6 sigma look for correlation and it’s easy to go too far and assume causation, but this is wrong.

This is an example. The daily average temperature (ºC, ºF) is correlated with the number of people (#) suffering a heart attack that day (and, probably, there is also a cause-effect relationship). The daily average temperature (ºC, ºF) is correlated with the amount of ice-cream (Kg) consumed that day (and, again, there is probably also a cause-effect relationship). However, the amount of ice-cream (Kg) consumed one day is correlated with the number of people (#) suffering a heart attack that day, but the probability of cause-effect relationship is low:


Find more examples here:

Some say that real causation can never be proved and therefore we only see correlation and imagine causation (more on this here). We can intuit that a cause-effect relationship is stronger than simple correlation. Anyway this belongs to the field of philosophy and in most cases common sense and observation can help us take an educated guess. The use of Ishikawa diagrams, 5 whys, DOE and PDCA experiments, besides the implication of the true process experts (those who work everyday there where the problem happened) can make a difference.

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Innovative Lean Leadership

Bob Emiliani’s Innovative Lean Leadership web page is full of knowledge and ideas. His experience and understanding of Lean tools and Lean leadership is evident. Both his blog and twitter account are really worth reading. I’ve chosen two great posts as an example of the content you can find at his page:

Some important learnings:

a) Lean was born “as a management system designed for buyers’ markets”, this is, when Demand is lower than Supply.

b) The importance of management involvement was already an issue at the time Lean was reaching America for the first time.

c) Early TPS training did not have any reference to VSM or A3 to explain TPS concepts like “flow” or “problem solving”.

Based on John Shook’s Lean Transformation Model, Bob adds extra information to the model and remarks the importance of the “Basic Way of Thinking” as the foundation for success: