A combo chart combines chart types to better represent the source data. It's a simple concept - when the chart's message doesn't stand out, rethink and redraw. There are many examples of combo charts, but to keep this one simple, we'll create a bar chart that compares monthly revenue for two years. Then, we'll redraw one of the series to catch a trend you might otherwise miss.
Let's suppose you want to chart monthly revenue for 2010 and 2011 using a column chart as shown below. As is, the chart's Okay. You can compare revenues by the month and discern that revenue is down from the previous year for some months. It's a bit harder to get the bigger picture.
Now, let's change the chart to a combo chart as follows:
- Click any of the 2010 bars. Doing so will select the entire series; each bar will display selection handles.
- Right-click the series selection and choose Change Series Chart Type.
- Click the first Area option.
- Click OK.
Now, you can clearly see the second quarter trend; the current year revenue dips below that of the previous year. That's information you can investigate. It's a small change, but the implications are huge.
Susan Sales Harkins is an IT consultant, specializing in desktop solutions. Previously, she was editor in chief for The Cobb Group, the world's largest publisher of technical journals.