When it comes to the maximum number of parts that should be shown as a pie chart, there are plenty of opinions floating around out there. In this article, I argue that the maximum number of slices depends on the situation and that, in certain situations, even a 30-slice (!) pie chart can be the best choice.
Read moreBig news! Practical Charts ON DEMAND will be available on June 25th!
An on-demand (pre-recorded) version of my flagship Practical Charts course will be available on June 25th! This self-paced video course consists of 6.5 hours of video in 44 lessons, and is available for 25% off during the pre-sale period (before June 25th).
Read moreWhen to use a bar chart
When should you use a bar chart instead of another chart type? Easy question, right?
As it turns out, choosing when to use a bar chart or another chart type is surprisingly complex. In fact, I’d argue that, in a way, bar charts are actually the most complex chart type. Sound strange? Then read this article…
Read moreThe one (rare) situation in which it makes sense to use a single stacked bar chart
I’ve recently seen a few comments on LinkedIn from people who don’t feel that it *ever* makes sense to use a stacked bar chart to show the breakdown of a single total. While relatively rare, there is a specific situation in which I think it *does* makes sense, though. What is that situation? Find out in my latest article...
Read more“Keep it simple” is NOT good chart-design advice
Creating “simple” charts is much harder than it sounds. Telling a chart creator to “keep it simple” is like telling a student driver to “avoid traffic accidents.” Well, yes, obviously, but how, exactly, does one do that? While avoiding accidents sounds simple, it requires learning hundreds of rules of the road and days of training and practice.
Read moreHow I wrote "Practical Charts"
I’ve been asked a number of times how I went about writing Practical Charts because it’s so, well, practical. This is a wonderful compliment to receive and so, as a cheap thank-you, here’s the story behind the book.
Read moreVideo: Choosing a chart type is trickier than you think - A conversation with Enrico Bertini
I recently had a great conversation with data visualization researcher and professor Enrico Bertini, about how surprisingly tricky it is to choose a chart type. Watch the video above (20 mins) to discover...
Why both the nature of the data AND the purpose of the chart must be considered when choosing a chart type
Why traditional "chart-type-chooser" diagrams and catalogues are often unhelpful, and even unreliable
Examples of more reliable and helpful chart-type-choosing decision trees from my Practical Charts course
Agree with what we said? Disagree? Great! Let us know in the comments below or in this LinkedIn thread.
Are “smoothed” line charts OK?
You’ve probably seen “smoothed” or “curvy” line charts like this before. Some people like them and others definitely don’t. In this blog post, I explain when I think it’s okay to use smoothed line charts and when they should be avoided.
Read moreAvoid problematic date formats in your charts!
You're looking at a chart and it contains a date labeled “10-02-2007.” What day is that, exactly? Feb. 10, 2007? Or October 2, 2007? How about “10-Feb-07”? Is that Feb. 10, 2007, or Feb. 7, 2010? To ensure that your chart readers know what the dates in your chart actually are, choose a date format in which:
The month is alphabetic (e.g., “Aug” instead of “08”)
The year is four digits (e.g., "2011" instead of "11")
As long as the date format that you choose checks both of those boxes, your readers will always interpret the dates in your charts correctly.
Read moreNew book announcement! "More Practical Charts" will be published on Jan. 16!
You read that right: MORE Practical Charts! 😉
My first book, Practical Charts, covers about 30 common chart types that are familiar to most audiences, such as bar charts, line charts, and maps. More Practical Charts covers 20 additional, more "advanced" chart types that tend to be unfamiliar to audiences without scientific or technical backgrounds:
Box plots
Merged histograms
Overlapping histograms
Distribution line charts
Distribution heatmaps
Merged bar charts
Scatter plots
Colored-dot scatter plots
Bubble charts
Scatter plot matrices
Pareto charts
Heatmaps
Shape size charts
Overlapping cycles charts
Cyclical heatmaps
Cycle plots
Strip plots
Jittered strip plots
Merged strip plots
Histograms
If you have a technical or scientific background, you might assume that most people know how to read most of these chart types but, after working with thousands of chart creators in hundreds of organizations, I've realized that that's not the case (unfortunately). There's a reason why you rarely see these chart types in the mainstream media: editors know that many readers/viewers won't understand how to read them.
If, however, you do create charts for relatively data-savvy audiences, by all means, pick up a copy of More Practical Charts 🙂. The book will be published on January 16th, but you can pre-order your copy now to get it shipped to you on the publication date. It's relatively short (about 100 pages) and is priced at less than half the list price of Practical Charts.
Why split these 20 chart types out into a separate book? Well, a large fraction of my readers can't use these chart types because their audience would struggle too much to grasp them, or simply wouldn't be able to grasp them. I didn't want to force those chart creators to buy and read content from me that they'll never use in practice, so I packaged that content in a separate, optional companion book.
BTW...
Interested in taking my Practical Charts course and/or my Practical Dashboards course? Registration for my January live, online workshop is now open (but it's already 50% sold out and early-bird prices end January 8th, so don't wait too long if you plan on registering). I hope to see you (online) there!
Have I resolved the pie chart debate? (New article in Nightingale)
For decades, chart creators have disagreed on whether pie charts should be used, but I think there are a few important arguments that have been missing from the debate and that might—just might—help to bring it to some kind of conclusion.
Find out what those arguments are in my latest article for Nightingale, the Journal of the Data Visualization Society.
How to quickly teach an audience to read an unfamiliar chart type
When creating charts for “everyday” reports and presentations, it's generally best to stick to chart types that you know are familiar to the audience. Sometimes, though, you can’t use a familiar chart type, either because there aren’t any familiar charts that can accurately represent the type of data to be shown, or because there aren’t any that can communicate the specific insights that you need to communicate about the data.
In these situations, you might have to use a chart type that you know is unfamiliar to the audience. For example, you might have to use a scatterplot or step chart, even though you suspect (or know) that the audience is unfamiliar with that chart type. What to do?
There are three techniques that I use to quickly teach audiences how to read an unfamiliar chart type:
Gentle reveal
Bait-and-switch
Duh insights
What, exactly, are these techniques? Let’s see some examples, starting with…
Read moreSix common pie chart formatting mistakes
There are six formatting mistakes that I commonly see in pie charts “in the wild.” This article discusses how to recognize and avoid those formatting mistakes in your own pie charts.
Read moreYou should probably be using “step charts” a lot more often.
If you haven’t been using step charts, there’s a good chance that you’ve been misrepresenting at least some of your data to your audience. That’s why I suggest that, if you can, try to start using step charts whenever you need to show irregular, persistent time series values, and start getting your audiences used to seeing this chart type.
Don’t know what a step chart is? Read this post!
Read moreInterested in reading the Practical Charts book before Nov. 15?
Looking forward to the release of the Practical Charts book on November 15th? Interested in getting a free chapter right now, reading an advance review copy weeks before the release date, and in helping others to discover the book? Want to pick my brain during invite-only “Ask Me Anything” Zoom calls?
Awesome! To get all of these benefits and other goodies, and to help promote the book, I’d love it if you were to sign up as a Practical Charts VIP Reader!
The tricky business of designing charts that will be printed in black and white
While less common nowadays, it’s still possible that you might need to create a chart that will be printed in black and white. For charts that were originally designed in color, just printing the color chart on a black and white device will often make it uninterpretable, so it must be redesigned. Redesigning a chart so that it only uses black and white can be tricky, though, and different design changes are needed depending on the chart type, number of data series shown, and a variety of other factors.
Read moreThe Practical Charts BOOK will be available on Nov. 15!
At embarrassingly long last, I’m relieved to announce that the Practical Charts book is finished! The book will be released on November 15th, with pre-orders beginning in a week or two.
The goal of the book is as ambitious as the course on which it’s based: to teach chart creators of any experience level to create expert-level charts in just a few days. Given how many common data visualization challenges and mistakes need to be tackled to accomplish that, it was a tall order to keep the book down to 300 pages, but, flipping through the advance copies that I just giddily unwrapped, I think it might actually deliver. You tell me, though, when you read the book (you’re gonna read it, right?). More details about the book can be found on the official Practical Charts book page.
There will be more book-related announcements in the coming weeks, so make sure you’re subscribed to my email list to be notified when…
Pre-orders can be placed so you get the book shipped to you automatically on the release date (you might even get an extra goodie or two from me if you let me know that you pre-ordered it).
Bulk orders for team leaders and educators are available (which will be before November 15th).
Free advance reviewer copies can be requested (we’ll be sending out a limited number of free advance reviewer copies so that there are reviews on Amazon when the book is released).
Sneak peeks of content from the book are released.
Also, make sure you're subscribed to my email list if you’re interested in becoming a “VIP Reader” of the book. WTH is a “VIP Reader”? Well, VIP Readers will receive perks such as preferential consideration when requests for free advance reviewer copies of the book are being considered, and access to private “ask me anything” Zoom group calls just for VIP Readers. In exchange, I’ll be asking VIP Readers to pre-order the book (so that Amazon’s algorithms quickly learn who to show the book to), then post a review on Amazon and chat up the book on their social media channels when the book is released in November. Interested? Awesome! I expect to put out the call for VIP Readers in one to two weeks via my email list.
Connected scatterplots make me feel dumb. (article in Nightingale)
Connected scatterplots are sometimes used to show how two variables are related over time. In my latest article for Nightingale (the journal of the Data Visualization Society), I argue that connected scatterplot are virtually never the best choice, and alternatives like stacked line charts and indexed line charts can communicate the same insights as connected scatterplots, but are much easier to read and less prone to misinterpretation.
Read moreThere are no bad chart types... Right?
There are about a dozen chart types that I don’t recommend using for “everyday” charts in reports and presentations, such as bullet graphs and box plots. Some people are uncomfortable with the idea of saying that a given chart type is never the most effective choice, however. In this blog post, I argue that there’s no reason to think that, for every chart type, there must be situations in which it’s the most effective choice, and that it’s entirely possible that some chart types are never the most effective choice.
Read moreShould you learn dataviz theory?
Occasionally, I come across a claim on social media that, in order to become truly competent at dataviz, you need to know about theoretical concepts such as graphical objects, encoding channels, and preattentive attributes of visual perception.
Is that true, though? Or can you still create effective charts without knowing about those theoretical concepts?
Read more