Scatter Plot Quick Select
September 16th, 2008 |
I recently had the opportunity to attend a talk by Ben Shneiderman, a big name in HCI and professor at the University of Maryland. He showed off a bunch of really cool visualizations he’s invented over the years, aimed at advancing the field of data analysis. One of the visualizations, the Rank-by-Feature framework, looked immediately useful to our product. It’s an overview of multidimensional data that uses coloring in a matrix of correlations. I decided to add it into Palantir Finance as a proof-of-concept.
We have a scatter plot in Palantir Finance, but it’s not designed to compare your data across many variables (called metrics here). I extended it by adding a small triangular matrix control that we call the scatter plot Quick Select. The control gives you a visual overview of the data, and allows you to identify interesting metric pairs and then drill down into a scatter plot for any particular pair.
Assume I want to view a set of 10 metrics (shown above). With our regular scatter plot, you have to choose two of these metrics and plot them to see their correlation. If you want to know how every possible pair of metrics correlate, you have to manually perform an O(n2) input operation.
With Quick Select, you enter the metrics once and the triangular matrix is formed. Each square in the matrix represents a pair of metrics, and each square’s color is the correlation between the pairs. For example, green is a strong positive correlation, light green a less positive correlation, white is no correlation, and red is a strong anti-correlation.
In the highlighted square above, we’re comparing percent return and correlation with the S&P 500 over the past year. The red shows a strong negative correlation. This makes sense in light of recent market behavior: the S&P 500 has not done well over the past year, so companies that were correlated with it also performed poorly, while companies that moved in the opposite direction performed well.
Drilling down to a scatter plot is as simple as clicking on the corresponding square. Below are 2 of the 45 possible scatter plots defined by this set of 10 metrics. You can quickly jump back and forth between different scatter plots while retaining a nice, condensed overview of the data in the triangular matrix on the left.
This prototype took less than a day to write. And it was written from outside the system, using only the pluggability points Palantir Finance provides. Overall it’s a powerful visualization component, added as an extension to the Palantir Finance platform, and done in under a day. Pretty cool!
Many thanks to Prof. Shneiderman for the idea.
