Dr. Steve C Wang used a data visualization technique called Chernoff faces to display some characteristic of baseball managers in 2007. The technique was developed by Herman Chernoff in 1973, and the idea behind it is to display different data attributes as facial features such as curvature of the mouth, length of nose, direction of eyebrows. In Dr Wang’s graphic, the number of lineups used by the manager is the length of face, width of eyes and ears; the number of pinch-hitters is the width of the hair, and the width of the face. Using this technique one can display many different attributes of a data set in a single face then allow the user to compare the different faces to analyse the data. In fact Chernoff claims that up to 18 data elements can be displayed using this method, allowing the user to visually cluster the data.

How effective are Chernoff faces in conveying information? Maybe the faces do not covey information at first glance, and they need a lot of referencing to the face legend, however I think they make an interesting and fun way of displaying information. The sole fact that this technique made the pages of the NY Times is enough proof of this. I’m sure that if the same data was displayed with bar graphs and pie charts it wouldn’t make any headlines. Most user studies in visualisation take into account the efficiency (speed in answering / accuracy of answer) of the technique, however techniques like Chernoff face maybe aren’t suited for answering questions fast, but they are catchy and media friendly.

More on Chernoff Faces
   Critique by Robert Kosara
   An Experimental Analysis of the Effectiveness of Features in Chernoff Faces
   Chernoff Faces in Psychology

Implementation
   Java
   R
   Excel