80:20 analysis

In simple terms, identify the few main factors that most influence your process and focus your efforts on improving those specific factors. Another way of looking at it is to determine the point of diminishing returns; that point where greater effort results in a correspondingly smaller improvement (i.e. 10% more effort results in 8% improvement).

Say you have a dozen known types of error which can occur in your system/process etc

80% of you problems are due to 20% of those errors.

Concentrate on fixing those errors first and you cure most of your problems.
The hard thing is identifying which are the critcal 20%...
So you need to record errors, analyse their causes, find which causes produce most errors and fix them first...

Common sense really.

Del,

I seem to remember you answering the same question about three months ago.

Nice link Milo. That should help. Ky.

If you sort the number of failures for any given system (or situation, or group of people, etc) and make a histogram of the causes of the failure against the number of failures, you will find that a large number of failures can be related to a few causes. Nominally, according to Pareto's Law about 80% of the failures will be due to ~20% of the causes. It is frequently the first step in isolating what needs to be done to improve process control.