(Bullets used to separate paragraphs...)

• This is actually a really good question, and the answer is maybe not obvious.
• The way I define data is "numbers that are related by a measurement system to an event of interest."
• So a list of random numbers is not data since it is unrelated to an event.  Importantly, this definition also implies that your measurement system links to the event somehow, highlighting the importance of good measurement system analysis.
• So, the process of observation can result in data, but without understanding the relationship your observations have back to the property of interest (as determined by your measurement system), observation does not necessarily result in data.
• Any measurement system (discrete or continuous) needs to be assessed for stability through time (control), agreement between systems (operator/machine etc), and agreement with a standard.
• Say a process generates discrete data (say a 1-10 rating on surface quality)  You would need to analyze the measurement system that generates that number. (Do the four inspectors using the Mark I Eyeball generating the rating agree with each other?  Do they agree with a standard?  Are these ratings repeatable through time?)
• I have seen measurement systems that themselves were not much better than random number generators, or whose measurements changed with time.  Those numbers were not data, even though they might have come from multi-million dollar instruments with digital readouts to four decimal places!
• Oh, as an aside, the relationship that the numbers (data) have with the event of interest as recorded by the measurement system dictates the measurement level the data are (nominal, ordinal, interval, ratio, absolute), which in turn determines what you are allowed to do with the data statistically.   So it is critical that you understand that relationship!

<edited to correct ambiguities>

I'm sure that as in everything, the quality of the Six Sigma BB training varies dramatically. I have been to several DOE training classes and many other statistical related classes. But the Six Sigma training I received through the Whirlpool Corporate Training Center was a phenomenal, mind-blowing experience.

The basic premise that the entire 5 weeks of training was centered around the following saying, "Practical, Graphical and Analytical".

It is my belief that if the project planning is done properly and at a level of detail befitting a "Black Belt", that many of the problems could be solved by using the "Practical" aspect of the Black Belt approach without spending wasted time with ineffective DOE's. But that depends on the level of the detail done as part of investigation into the process. If done properly, the BB will have identified, not just the inputs, transformations and outputs, but the interactions, interdependencies, controllable variables and the noise variables. If a process mapping approach is used, then the known’s and unknown’s will also be identified. This also includes a detailed investigation into what the perceived problem or project really is. I believe that if this phase is done correctly, the scope of the project or even what problem is being address might change some from the initial starting point.

I also believe that another common mistake is that organizations are convinced that a single DOE will provide a magical answer or the absolute perfect process. One of the first things I learned in the Whirlpool training program was that doing a DOE was a process. An iterative process that might only give you a hint of the direction you need to head, and rarely the optimal answer on the first DOE.

Too many times I have seen people quick to run a DOE to solve a problem they didn't even fully understand. Then when the analytical aspect of the DOE did not yield and magical solution, they would become skeptical of DOE's in general.

To me, the Black Belt training I received would still be well worth the effort if we had spend almost no time on the Analytical aspect of the training program. The planning, the understanding of the process, the critical thinking involved in a well done thought map has benefited me almost on a daily basis. The statistical and analytical knowledge I gained has been extremely helpful, but the initial aspects of approaching a problem and the planning and process investigation has forever change the way I approach things on a daily basis.

I'm not trying to negate the value of the analytical aspect but so many times, the use of the analytical tools only will not of much value without the initial part of the process.

thanks,

Terry A. Henson