Saturday, January 24, 2009

Visualizing Enrollment Change with Class Trajectories

Visualizations like graphs and animations are of obvious value in presenting data. One of the more useful ones I've found for visualizing enrollment is what I call a class trajectory graph, an example of which is shown below (with made-up data).

It shows three classes for four-year programs entering in fall 2000, fall 2001, and fall 2002. The right-most point on each of the trajectories is the first year for those students, and shows enrollment and net revenue per student (tuition minus institutional aid). Multiplying those two numbers gives net revenue for the whole class, which can be compared to the level curves graphed. So one can see that the freshman year for the 2000 entering class netted the institution around 9 million dollars. As time goes on, the classes get smaller because of attrition, so the next point on the blue line is to the left. Also note that net revenue per student fell somewhat. This is normal as students with leaner aid packages attrit at a higher rate. In the second year, the 2000 entering class netted the institution a little less than $7.5M. The entering 2001 class was bigger and produced more revenue per student, so the right-most pink point is up and to the right. It generated about 12 million its first year.

These trajectory graphs quickly convey important information. How bad is attrition, and what does it cost us in net revenue? How big are the classes comparatively? What are overall trends in class sizes--useful for planning everything from budgets to residence halls to class offerings. This is an essential graph for your strategic dashboard.

Bonus. Here are two other two visualizations just for fun. The first one [here] shows you how zip codes are clustered. Could be useful for something, I suppose, but mainly neat to play with.

The second [here] is just plain (or plane in this case) cool. The video shows world-wide flights over 24 hours.


  1. Joshua Nypaver9:11 AM

    I wonder if there is a way to mash up these two concepts, perhaps to use color coding to show attritition levels over a span of time span by zip code and animating it to if you end up getting a large amount of attrition from one particular area. Of course, if your student candidate pool all comes from one specific pool, this may not be as helpful...

    I had seen the plane movie before, but having had flown before, I think it would be interesting to see the same data, only show flights that do not leave on-time in a contrasting color. I think it would be interesting to see the amount of late planes throughout the day increase as schedules get thrown out of wack due to delays, etc. and you might actually get a suprise in how many flights actually get there on-time.

  2. Neat idea--geotagging can definitely be useful for figuring out where attrition comes from. An animation showing the whole admit-to-grad lifecycle might be cool. Little dots that age or burn out unless they become little stick figure grads. We currently don't have the data to pull that off, but otherwise wouldn't be too hard to do in Flash.