In this edition of Chart Busters, I’ve taken on a charting tutorial on the Microsoft web site. I know they are trying to help their customers make better use of their software, and some of the Microsoft tutorials are really pretty good. They have some helpful pages on using pivot tables, for example. But this charting tutorial is an absolute disaster.
The tutorial in question is entitled Charts III: Create a professional-looking chart, and it is the third in a series of four tutorials. The others are Charts I: How to create a chart, Charts II: Choose the right chart type, and Charts IV: Charts for the scientist. I will probably review these other tutorials at some point, but this one is really a job for Chart Busters.
Before I begin, I’d like to thank Jorge Camoes, whose Spiffy Charts: Want to know how to create bad charts? Visit Microsoft Office Online Training blog post pointed me to this horrid tutorial.
I’d also like to acknowledge all of the bloggers and commenters who have bemoaned the fact that “making a professional chart” is really a nice sounding phrase that really means “use as much gratuitous formatting and effects to make your chart pretty, without regard for its effectiveness.”
Tutorial Example Chart 1
Microsoft kicks off their tutorial with a simple column chart that uses the defaults of Excel 2003.
The first thing the Microsoft tutorial suggests is removing the gridlines. This is perfectly reasonable as far as it goes.
But it really doesn’t go far enough. Let’s really clean up the chart (below left).
- Remove the border around the entire chart.
- Move the chart and axis titles close to the edges of the chart area, and stretch the plot area into the freed up space.
- Take away the plot area fill and border.
- Remove the tickmarks from the X axis.
- Move “First Quarter Sales” to below the title, so it’s more of a subtotal. If the X axis has dates, you probably don’t need an axis title.
- Remove the border around the legend, arrange the legend entries horizontally, and move the legend beneath the chart.
And the gridlines wouldn’t be bad if they were lighter. This allows the Y axis line to be removed (below right).
Next the Microsoft tutorial suggests putting all of the data into data labels in the chart. This renders the Y axis redundant, so it can be removed.
It may make sense to add data labels to some points, but putting a label on every point clutters up the chart. It makes one ask, why not just use a table, if the individual numbers themselves are so critical? I like my chart with labeled gridlines and no axis.
The third Microsoft enhancement to the chart is to start adding gratuitous formatting. Add a gradient background to the plot area. Add a different gradient fill to the data bars.
Well, if we add a gradient, we will no longer have a nice uncluttered chart background. So let’s ignore that advice. As far as the pseudo-columnar appearance of the columns, that’s distracting, because folks are going to spend more time thinking about how we accomplished that cool formatting. Se let’s skip that one, too. But there’s nothing wrong with using nicer colors. Here’s my updated chart with axis (below left) or with gridlines.
The fourth enhancement to this simple chart is to remove the border from the legend. Hmm, I think we’ve heard that somewhere before. Also, the tutorial suggests adding a shadow to the chart. However, that means adding back the border, which with the shadow would make the chart even more cluttered.
The best piece of advice in this step is (emphasis mine):
You could add shadows around the chart and axis titles as well, but make sure the chart doesn’t look cluttered.
Chart Axis Sin
The final enhancement Microsoft wants to apply to their chart, after changing the product name, is to change the axis scale. In some cases this is acceptable, even desirable. However, bar and column charts encode their values by their length. When you shorten the axis, you effectively cut the bottoms off of the bars. This makes the longer bars seem much longer in comparison to the shorter bars than they really are.
Why start the axis at 50? Why not at 100? This makes the increases from January to February all the more striking.
This is a a major chart fail. The value axis on a column or bar chart should always include zero. Always. If you want to expand the scale to help resolve the values, then a column chart is not the right chart type.
Scott Ziolko commented below that a further improvement to these charts would be to rotate the Y axis title to make it easier to read. In the chart below left, the axis title has been rotated and moved above the axis, and the plot area was widened (alternatively the chart could have been made narrower with no loss in resolution). In the chart below right, I have incorporated the axis title into the chart subtitle, where it is just as effective.
Chart Type Selection
Speaking of the right chart type, it is generally more effective to show time-based data in a line chart, i.e., in a time series (below left). When the axis is rescaled (below right), there is no loss of meaning or distortion of data.
Tutorial Example Chart 2
The next chart is “a combination chart that needs help.” And it does need help, but I think the “after” chart needs as much help as the “before” chart.
My first thought is about which series was assigned to which chart type. To me it has always made more sense to use columns for the Projected or Target values, and show the Actual values with a line. Alternatively, an area series could show the Projected or Target values.
What also looks better is a chart without all those distracting borders. Removing the fill helps too. I found it a bit hard to look at the green and gray chart above: the clashing gradients made the bars hard to pick out.
I also found it unusual that the Actual values showed a steady progression from month to month, while the Projected jumped around. Maybe they did get the chart types correct, but the labels wrong. Of course, it is just data made up for the benefit of this illustration.
Tutorial Example Chart 3
The final chart in the tutorial is one of my favorite types (cough cough): a 3D column chart.
The tutorial correctly points out that the tall bars in the first chart below obscure the short bars. They spoil this observation by simply moving the tall bars behind the short ones. Does this make it any easier to compare their values?
The strange perspective eliminates any chance of understanding the relative values in this chart. Especially since the vertical axis tick labels in the second chart have been deleted.
The tutorial blindly follows the mantra: If 2D are good, 3D must be better. But for clearly displaying data, 2D rules. In both charts below, the 2D column chart and the line chart (hey, it’s a time series!), make comparisons easy.
I guess the takeaway here is that no matter how much effort is spent generating pretty tutorials, if the rules and best practices are not followed, the tutorial will not succeed. It illustrates how the producer of a software package may not be the best to advise users how to apply the software.
Keep your wits about you when seeking help, look for multiple sources of advice, and use good judgment when following that advice.