Two Universal Metrics We Can All Measure and Improve

Have you ever heard someone say “You can’t measure what I do!” Or maybe this one: “We are a job shop – we don’t do the same thing over and over – so we have nothing to measure.” Most likely you have if you are involved in process improvement, in using SPC, or getting people to take data and track it over time.

The reality is that you can easily find things that should be tracked over time. But there are two universal metrics that we can all measure and track over time. These two are described below.

The first one is rework . Yes, rework. We all do it. I am...


What Happened to the Complete Game?

In 1968, Bob Gibson, a pitcher for the St. Louis Cardinals started 34 games. He finished the season with 22 wins and 9 loses, with an earned run average (ERA) of 1.12 and 13 shutouts. He had 268 strikeouts. He was one of the best pitchers ever in the major leagues.

Most amazingly, he had 28 complete games in that season – he finished 28 of the 34 games he started. Last year the National League (NL) had a total of 17 complete games while the American League (AL) had 25 complete games – both less than Gibson’s total by himself in 1968. Where did the complete game go?


range chart

How is Sigma Estimated from a Control Chart?

Sigma – an important statistic for us to know. Sigma, or the standard deviation, is a measure of how much dispersion there is in a process. There are numerous ways to estimate sigma. One way, of course, is simply to calculate the value using the formula for the standard deviation:

where X i are the individual results, X is the average and n is the number of individual results.

This is a measure of the dispersion in the data. But is it a good one to use? Does it fairly represent the data? The answer is you don’t know because you haven’t...

What is the Analysis of Ranges (ANOR)?

Our last blog - What is the Analysis of Means(ANOM)? - explained how ANOM is used to determine if there are differences in treatment means from an experiment. ANOM answers the question:

“Are there any significant differences in the treatment averages?”

The Analysis of Ranges (ANOR) is very similar to ANOM, but ANOR focuses on the within treatment variations. ANOR answers this question:

“Are there any significant differences in the within...

What is the Analysis of Means (ANOM)?

There are times we want to compare things, e.g., different machines, different raw materials or different shifts. There are several ways to do this statistically, but visual is always best. And the best visual technique for comparing things is the Analysis of Means (ANOM) method.

Suppose you have five different treatment methods you are considering for coating parts. For each treatment method, you coat four parts and measure the coating weight. For each treatment method, you calculate the average and the range. Of course, the treatment averages are not usually the same. This is not...

ANOX Chart

What is the Analysis of Individual Values (ANOX)

You have just finished a pilot production run for a new product. You want to know if the data you have are homogeneous, i.e., they come from one process and there are no outliers. How do you do that? In the past, I simply put the data on an individuals (X-mR) control chart. If the chart was in statistical control, I would assume that the data were homogeneous.

That changed when I read a 2017 article by Dr. Donald Wheeler and James Beagle III that described a new test for homogeneity. The problem with using a control chart to do a test for homogeneity is that the number of data...

hardness tester

What is Evaluating the Measurement Process (EMP)?

It is time to replace the average/range method and ANOVA method for Gage R&R studies. Evaluating the Measurement Process (EMP) is a collection of techniques that allows you to discover much more about your measurement process than if you just use those traditional techniques. EMP has been developed over the years by Dr. Donald J. Wheeler.

The experimental process is essentially the same. One or more operators, measure one or more parts, multiple times. The difference is that EMP immediately places the results on a control chart to assess how consistent, reproducible, and...

It is Your Fault!

You are a front-line operator. Who gets the blame when something goes wrong? Far too often, you do – the operator. You are doing the work. Of course, it is your fault! Have you heard these reasons for why it is the operator’s fault?

  • He didn’t follow our job work instructions. These are written out and the operator has been trained.
  • He wasn’t paying close enough attention.
  • The equipment is down because the operator didn’t run it correctly.
  • She didn’t take time to re-check her work.
  • He simply doesn’t care.

Blaming the...


Dr. W. Edwards Deming and Profound Knowledge

Have you heard of Dr. W. Edwards Deming? Do you remember who he was? Dr. Deming was one of the great “quality gurus” back in the 1980s and 1990s. (Photo courtesy of The W. Edwards Deming Institute®.)

He is often credited with helping the Japanese rebuild their economy after World War II. Dr. Deming spent years developing a methodology to help companies move forward. It is still valid today. He called this methodology his “System of Profound Knowledge. This system is composed of four bodies of knowledge:

  • Appreciation for a system
  • Knowledge of variation
  • ...

Variation and the Funnel Experiment

Our last blog, The Red Bead Experiment, described a simple process to teach variation to everyone. This blog describes another simple experiment that shows the danger of not using the knowledge of variation you learned from the red beads.

Dr. Deming said, "If anyone adjusts a stable process for a result that is undesirable, or for a result that is extra good, the output that follows will be worse than if he had left the process alone." This is often called tampering with or over-controlling the process.

For example, a...


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