Time to Lose the 10-Minute Overview

Stop the self-sabotage and help executives understand simple variation

I attended a talk in 2006 given by a world leader in quality that contained a bar graph summary ranking 21 U.S. counties from best to worst (see figure 1). The counties were ranked from 1 to 21 for 10 different indicators, and these ranks were summed to get a total score for each county (e.g., minimum 21, maximum 210, average 110. Smaller score = better). Data presentations such as this usually result in discussions where terms like “above average,” “below average,” and “who is in what quartile” are bandied about. As W. Edwards Deming would say, “Simple… obvious… and wrong!” Any set of numbers needs a context of variation within which to be interpreted.

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Comments

Great Article, as usual

Davis, I'm glad you were able to do something with this!

10 minute overview & one number summaries

Davis, until financial reporting steps out of the dark ages in this area I don't believe we'll see much widespread progress. Look at the emphasis on comparing this time period to the last period and the one last quarter and year! These are snapshots of financial health which can and often are manipulated to look good. I'm reminded of a conversation I once had with a PhD chemist about statistical methods and in particular DOE. He asked "If these are such great methods why aren't they being taught in chemist PhD programs?" Until business, financial and MBA programs start teaching a better way, we'll have a tremendous problem making a real difference. Why aren't the best business schools teaching about the impact of variation? Why don't the big consulting companies advise their clients about how variation can make so many "conclusions" erroneous? Which company's annual report is filled with trend diagrams, not pie and bar charts? Why don't we see more sparklines?