Interactivity as overhead

Making data graphics interactive should improve the user experience. In practice, interactivity too often becomes overhead, making it harder for users to understand the data on the graph.

Reader Joe D. (via Twitter) admires the statistical sophistication behind this graphic about home runs in Major League Baseball. This graphic does present interesting analyses, as opposed to acting as a container for data.

For example, one can compare the angle and distance of the home runs hit by different players:

One can observe patterns as most of these highlighted players have more home runs on the left side than the right side. However, for this chart to be more telling, additional information should be provided. Knowing whether the hitter is left- or right-handed or a switch hitter would be key to understanding the angles. Also, information about the home ballpark, and indeed differentiating between home and away home runs, are also critical to making sense of this data. (One strange feature of baseball fields is that they all have different dimensions and shapes.)

But back to my point about interactivity. The original chart does not present the data in small multiples. Instead, the user must "interact" with the chart by clicking successively on each player (listed above the graphic).

Given that the graphic only shows one player at a time, the user must use his or her memory to make the comparison between one player and the next.

The chosen visual form discourages readers from making such comparisons, which defeats one of the primary goals of the chart.