If It Don’t Fit You Must Forget
Trendlines are often fake news. How can you separate fact from fiction? It’s easy.
“I’m Jay Arthur, author of “Lean Six Sigma Demystified” and QI Macros [software].
“One of the things that really irritates me about Excel is it’ll add a trend line to any data, but it does not add a “goodness-of-fit” metric automatically. It’s called “R squared,” and R squared should be like .8 or 80% fit in general.
“I’ve seen lots of charts and lots of posters at lots of improvement conferences where the goodness of fit metric is less than 50%. What?! So it’s not really an improvement.
