Friday, April 10, 2015

Rating Shaves by the Numbers

Putting a number to a subjective evaluation gives a sense of clarity. It gives a handy way to make comparisons that would otherwise be difficult.

This is what I did when I sketched out my shave-rating system. And it has been a success.

Well.... actually no, it hasn't.

If assigning numbers is difficult (and it is), it's even more difficult to tease some meaningful information out of those numbers. This is why the discipline and science of statistical analysis was created.

The famous statistician and business consultant, W. Edwards Deming, showed this clearly in his master work, the book Out of the Crisis. He used the example of dropping a marble through a funnel-type devise onto a target. The goal of this experiment was to create the tightest scatter pattern of outcomes after repeated dropping of the marble onto the target.

The most intuitive method was to adjust the dropping device after each trial, and the adjustment would compensate for the degree of error in the previous drop. Kind of makes sense, right? If the marble drops a centimeter to the left, then move the dropping device one centimeter to the right. Outcome should be perfect!

But no. Actually, using this method of adjustment cause the scatter pattern to explode with variation, creating not an orderly, accurate outcome, but instead a chaotic mess with no accuracy, no increasing repeatability at all.

The best result was when the outcomes were analysed using statistical methods, which resulted in the scatter pattern decreasing, and the outcome of the marble drops becoming increasingly focused, more precise.

So the rating system that I've devised -- imperfect though it may be in and of itself -- is only a crude baby step in comparing gear and shaves. Though this baby step can use much refining, the biggest hurdle would be to apply statistical methods to actually begin the process of gleaning meaningful conclusions from the numbers.

A rating system isn't a mistake; it's just not the complete answer to understanding the truth that may be hidden in the numbers.

Food for thought.... and analysis.

Happy shaving!

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