All entries for Wednesday 12 December 2012
December 12, 2012
Almost every company compares one number with another number. It is so easy to do and to their point of view this comparison can provide the evidence that process is below or above the target. Is it? Can we really judge how good our business operating by such simple comparison?
All information that we get from others we put in the context. So why then figures and numbers should be considered independently? Statistical Process Control suggests to build a flow chart and then also put natural limits of the process, thus, to present figures and numbers in the context. This is reasonable and it makes sense, BUT…what I cannot understand and agree with is that this traditional ways of communication with numbers are considered to be useless.
As Wheeler states this comparison cannot filter out the noise of the process. Why not? For example, if we develop target with taking into account economic environment and seasonality (two noise factors) and compare it versus actual numbers in this way we do filter out the noise of the process. After that we can use obtained data and put it into the context by using control chars. I do believe that this traditional comparison is useful. If not, then why everybody is still using it?