Here are two ways to display a relatively large dataset, montly unemployment rates by state since 1976. The first one, above, is perfect to see the overall patterns, the range from the lowest to the highest, the outliers and the slopes. An interactive version would allow the user to highlight specific series.

A small-multiple version allows the user to focus on specific states, compare them to the normal band, etc. States are ranked by labor force size and, as you can see, in the first row seven out of ten are above the US average in April. In the last row, only one is above the US average. You can also see that Michigan was not well (unemployment-wise) long before the current crisis, or a spike in Luisiana (Katrina). It pays to study this chart carefully.

Bottom line: try to see the same data from different angles. There will always be semething interesting to find.

What do you think? How would you improve these charts? Would you use a different display? Share it in the comments! (here is the data file)

Update: I usually stay away from Excel’s surface charts, but I’d like to add this one:

Also check Michael’s Horizon chart.