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Sander Viegers Rides Again

Today we have a second guest post from Sander Viegers, a user experience designer who worked on many aspects of Excel 2007.  Sander’s previous post is located here.

In my previous guest post (thanks for all the feedback) I talked about the holistic design approach to redesigning the entire charting experience. In this blog post, I would like to give an example of a very specific design problem: getting the data to show up correctly on your chart.

Same Data – Two Different Charts

The problem we were trying to solve was: how to provide an easy way for users to change from the chart on the left to the chart on the right (see image 1). A quick analysis of the two images tells you that the labels on the axis and legend are swapped. If you then look closely at the data table, you can see that in the chart on the left, the bars represent the data that is shown in the columns of the table. In the chart on the right, the bars represent the data that is shown in the rows of the table.

From usability studies with the implementation of this feature in Excel 2003 we learned three things: 1) users often have a clear idea about which of the two chart variations they want to use; 2) Half of the time Excel gives the wrong chart; 3) Users were not able to switch between the two chart variations. In conclusion, being able between the two variations was an important task that many people were struggling with.

Image 1: same data – two different charts. Users know which one they want but cannot figure out how to switch from one to the other.

The Problem: Series…

First we did an analysis of the feature to figure out what exactly the problem was. We went through all the paths users can take and the steps users need to go though to complete the task. With each step we described the problems. There are three ways to switch from one chart variation to the other:

1.       Use step two of the Insert Chart Wizard.

a.  Most users click “Finish†after the first step of the wizard and never see this option.

2.       Right Click on the chart and choose “Source Dataâ€.

a.  From all the right click menus it is not obvious that “Source Data†is the one that brings you to the dialog where you can make the switch. It could just as well have been Chart Options…

b.  In the dialog there is no link between the terminology and what you see in the chart. The dialog has the option to change from “series in rows “ to “series in columnsâ€. But it does not become clear what series are.

3.       Use the toolbar toggle buttons.               

a.  The toolbar also relies on understanding the concept of “series on rows†and “series on columnsâ€. Many people also close the toolbar and there is no easy way to get it back.

From this analysis, the design goals for this feature were to make it discoverable and easier to use.

Image 2: User interface in Excel 2003

Solutions and Lab Studies

We tested many solutions in a usability lab study. Image 3 shows some of those solutions. One of the solutions was to make this choice part of the Insert Chart Dialog. It appeared that users simply overlooked the option when they concentrated on the task of choosing a chart type. In another solutions we used previews of the chart that showed both options. We found that those previews were always too small. A solution that showed the labels on the axis and the labels on the legend inside the dialog made it easy for users to make the connection between the dialog and the chart.

Image 3: Some of the solutions that were considered

Final Design

In our final design , shown in image 4, we’ve made a clear link between the chart and the dialog. We made the switch is very visual by showing an arrow that illustrates what happens when you click the button. The same button is surfaced in the first ribbon tab that comes up after inserting a chart.

Image 4: Final design