Hi

Can anyone advise me what is structured variation and BW Chart?

Do you have any material on these that I can read?

Thanks in advance

KT:)

Please provide additional context about these terms. What industry/field are you in? Where did you hear of these terms?

Structured Variation probably refers to the concept that not all observed variation is truly random, but varies according to specific rules that may not be understood, but can be studied and modeled. An example of this might be a raw material purchased from two different suppliers. Whenever, the material is changed from supplier A to supplier B and back, a change in variation is observed.

There are many types of BW charts, which probably do not relate to your question (e.g., BusinessWeek stock charts, BirthWeight charts, etc.). In the context of Structured Variation above, I suspect that BW charts refer to Between-Within variation, although I have never heard of them called BW charts.

Between-Within refers to Rational Subgrouping for Xbar/R charts. Xbar/R charts are not only used for process control, but can also be used to statistically analyze data. The Xbar chart displays the variation between different subgroups, and the R chart displays the variation within the subgroups.

The analysis method starts with creating a "tree diagram" with the total observed variation at the top and breaking out the different sources of variation below that in a tree root-like structure. You then collect rational subgroups of data to fill in the entire chart. Next, plot the subgroup data in the Xbar/R charts starting at the highest level. Then work your way down through the lower levels creating a new chart for each level. Careful analysis of each chart (Xbar AND R) for each level will identify the major sources of the observed variation. Once you have the major sources identified, you can then control them.

Thanks for your advise.

I come from the electronic industry which the company is making media for the disk drive industry.

Thanks and regards

KT Chua:bigwave: