They’re so hot right now, sparklines. They thankfully bring some sanity to performance dashboards (goodbye goofy gauges). But they do have a limitation no-one seems to be talking about…
Sparklines are the crafty invention of statistician and data display guru Edward Tufte, and presented to the world in his book Beautiful Evidence.
A sparkline is a tiny line chart stripped down to its essential function of showing the time series of a specific measure. They are so tiny they can easily be embedded into text, tables and other tight spaces.
Little wonder Stephen Few has embraced them in his landmark book Information Dashboard Design.
I like them because you cannot manage performance when you’re looking at pie charts and gauges and dials. You need to see change over time.
What’s more, you need to separate the signals of change from the noisy variation that exists in any measure’s time series. And that’s where I think sparklines meet their limitation.
Sparklines still encourage you to focus too much on the first and last values of your performance measure, rather than the true signals of change that are based on the patterns in the time series, not the points.
Separating signals from noise, and drawing your eye to patterns rather than points, is something XmR charts do well. XmR charts are a specific type of statistical process control chart, discussed in detail (very interesting and readable detail) in Donald Wheeler’s book Understanding Variation.
They are graphs with 3 very important features that make performance measures so much easier to interpret validly.
I wondered what would happen if sparklines courted XmR charts? So I played with it and ended up with something that I reckon absolutely rocks. You get a tiny graphic that works well in text, tables and dashboards AND it is easier and faster and more valid to interpret what performance is really doing.
I call them ‘smartlines’. (I would like to call them ‘XmRtlines’, but pronounced ‘smartlines’ – too cryptic though, I think.)
What do you reckon, Stephen Few?
TAKE ACTION: Take the time to learn about XmR charts, and when you build your dashboards, give the smartlines (or XmRtlines) a go!
Very interesting. I like sparklines, too, and I certainly like XmRt charts. Can you pls explain how how you creates XmRtlines? Are they in the excel menu options?
George, Excel does not have XmR charts or my my little invention of Smartlines. You have to set them up manually, or you can take my online course at www.usingsmartcharts.com to learn how and get templates.
Stacey – very interesting! Nice to correlate the concepts. What do you think of this slide deck on XmR charts?
Maybe you could do a nice, short version of this directly in your post above so that folks can get an idea quickly with some potential references where they can get more info. At least give us an example of your smartlines! And hopefully, you don’t let what Mr. Few says impact you either way – your ideas and concepts are outstanding! Thank you for sharing!
Mike, I am not sure how I can put images in my blog posts here on kpilibrary. Until I find out how, you can view a version of this blog post with the graph images at http://www.staceybarr.com/measure-up/are-sparklines-smart-lines/
Thanks for sharing your presentation.
Yaaay, Stacey! Thanks for the inventive mashup of XMR charts and sparklines. I’ve been evangelizing for XMR charts ever since I learned about them in Six Sigma training eight years ago. They present very helpful context that is lacking in most key process metrics. Finding a way to compress them to sparkline scale while still preserving the richness of the original XMR presentation is very clever work on your part. Way to go!
You’re a sweetie, George! So glad to meet another who is as passionate about “truthful” measurement as I am. All we need now is to find a developer who can automate the creation of smartlines (or at least XmR charts) in reporting and dashboard software…