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Line charts with trend lines are fake news. Here’s why:
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“Hi, I’m Jay Arthur, author of “Lean Six Sigma For Hospitals” and QI Macros [software].
“I was at the Institute for Healthcare Improvement conference, and I go through and I look at all the post-improvement posters that are out there. I saw “Nurse Betty” (that’s what I’m going to call her) and she was standing in front of a poster and she was studying it. She was wearing a nice blue pantsuit [and] comfortable shoes because it’s a lot of walking in these conferences, but she was staring at it like crazy.
Continue Reading "Line Charts with Trend Lines are Fake News"
Posted by Jay Arthur in Improvement Insights.
Ever seen a line chart with a trend line that implies there was great improvement? Probably not. Here’s why:
“Hi, I’m Jay Arthur, author of “Lean Six Sigma For Hospitals” and QI Macros [software].
“If you’re listening to anything in the news, they always talk about “fake news,” right? Fake news: somebody made stuff up. But in my experience, when I’m wandering around [seeing] all of these presentations and poster presentations at trade shows and stuff, I keep seeing all these line charts with trend lines in them. “Oh look! We have a trend line! It’s reducing whatever it is,” right?
Continue Reading "Line Charts with Trend Lines are often Fake News"
Posted by Jay Arthur in Data Mining, Improvement Insights, Six Sigma.
Line charts with trend lines can be misleading. They can provide a kind of “false positive” that implies improvement where there is none. Here’s why:
“Hi, I’m Jay Arthur, author of “Agile Process Innovation.”
“I go to all these trade shows and I see a lot of poster presentations but they’re using line charts and then they draw a trend line through them and then they say, “Oh, we made an improvement.” No you didn’t. If it doesn’t really fit the line very well, if your goodness-of-fit metric is less than 80%, I’m not buying it. But nobody gives me a goodness-of-fit metric called r-squared, they just show me a line graph or a bar chart and then they show a little line through it.
Continue Reading "Trends Are Not Always Improvements"
Posted by Jay Arthur in Improvement Insights.
At the 2018 Magnet Nursing conference in Denver, I saw many improvement posters using line or bar charts with an added trend line to show improvement. Unfortunately, few of the trends were valid. Here’s why:
Continue Reading "Trendlines Are Rarely Improvements"
Posted by Jay Arthur in Improvement Insights, QI Macros, Statistics.
