Pareto: chop off the head or trim the tail?

A Pareto chart is an ordered histogram where the few categories with highest occurrences are on the left side (the head), and the many categories with few occurrences are on the right side (the tail). A Pareto chart is used to discriminate the vital few from trivial many, especially if the distribution complies to the Pareto law stating 20% of all the causes accumulate 80% of all effects.

It is commonly accepted that efforts to solve problems should focus on the Pareto chart’s head as the leverage is most important: solving 20% of the causes eliminates 80% of the effects.

The 20/80 law is important for rational decision-making, optimizing the Return On Investment of problem solving investment vs. problems solved, or put slightly differently: the ROI of cost of problem solving vs. savings related to problems solved.

All books will tell the same: chop off the head

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Yet things are not that simple. While the above is important for management, executives and bosses, personnel struggling with daily problems see the things differently.

In the tail of a Pareto chart of problems are all the smaller difficulties, annoyances and broken items or processes that are nevertheless itching the executant every day, sometimes every minute. Unfortunately for those victims, the matter is not seen serious/costly/risky enough to draw attention of the brass, all focused on Pareto’s chart head.

Team leaders or foremen don’t dare going against the 20/80 rule and distract time or means to fix minor problems. These minor problems remain in the chart’s tail as minor problems, as solved major issues will be replaced by new majors problem. Minor problems remain in the chart’s tail even they get unbearable by those affected.

No wonder if, in order to get attention, those problems are exaggerated, sometimes extended. The “help yourself solutions” range from giving up to ask for repair and improvement (and keep suffering in silence) to actively sabotage and worsen a situation so that management must act.

  • A worn out tool won’t be replaced before it is totally broken? Just break it.
  • Maintenance will not show up until total breakdown? Give the trouble some help to stop the machine.
  • The circuit breaker breaks constantly? Put some tape or stick a match so the lever cannot move, replace fuses with stronger ones or a nail.
  • Random stoppages need to inhibit safety devices to fix the problem and start again? Let the safety devices constantly out.

Lack of attention to so-called minor problems is not only denying respect to people, but can lead to deviant behaviors with potentially high risks for safety, quality or machine/equipment life.

The irony of this kind of situation is that the so-called minor problems are usually easy, quick and inexpensive to fix/solve, while the major issues require more time, efforts and money to get fixed.

Dual approach

For many years now I teach and advise to approach problem solving with pragmatism, focusing on the big issues as 20/80 law tells but in the same time solve as many minor, Pareto chart’s tail problems as possible.

I call this the dual approach or pincer movement if you will.

The main reason is that personnel need evidences that continuous improvement program, lean transformation or whatsoever is going on yields benefits they can assess. This means the improvements have to be quick and solve their daily itching problems.

If this is not done and results in focusing only on major problems show up after several weeks or months, personnel will have lost confidence long before first results show. Conversely, if the simpler problems are fixed swiftly, people will see concrete and fast improvement with some benefits for them. They’ll be much more interested in participating and supporting the program.

Therefore, Pareto chop off the head AND trim the tail!

Feel free to comment or share your own experiences.

Bandeau_CH11
View Christian HOHMANN's profile on LinkedIn

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