Line Chart – Lean Six Sigma Moneybelt

Improvement Insights Blog

Posts tagged "Line Chart"

Line Charts with Trend Lines are often Fake News

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?

Posted by Jay Arthur in Data Mining, Improvement Insights, Six Sigma.

Trends Are Not Always Improvements

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.

Posted by Jay Arthur in Improvement Insights.

Why Are People Using Line and Bar Charts, not Control Charts?

If you look at improvement project posters at quality conferences around the country, you’ll find that almost everyone is using Excel line and bar charts. Even after decades of Six Sigma training and association membership. What’s the hold up? Here’s my take:

“Hi, I’m Jay Arthur, author of “Lean Six Sigma Demystified” and QI Macros [software].

“Every year I look at lots of improvement posters and I keep wondering, “Why isn’t anyone using the tools of Quality?” Control charts, Pareto charts, histograms… Most of them are just using plain old Excel line and bar charts. Now it might be because they don’t know about the power and beauty and how easy it can be now to do Control charts, Pareto charts and fishbones.

Posted by Jay Arthur in Improvement Insights, Lean, Six Sigma.

Line Charts Are Like Driving in a Blizzard

What charts do you need to stay safe and in control?

“Most of you have driven on a highway. It may have been a two-lane rural [road] or a four-lane interstate, but you know that the lines on each side of the road help you stay on track, keep you safe and know that you’re going in the right direction.

“But if you’ve ever driven in a blizzard, you know all those lines are totally obscured and you can hardly see. I had to go over Raton Pass once upon a time driving from Denver to Tucson to see my parents, and it was a pouring blizzard and I could barely see where I was going.

Posted by Jay Arthur in Improvement Insights, Six Sigma.