Ross Petchler / 15 May 2013
WesMaps, Wesleyan’s online course catalog, is essentially a directed network in which courses correspond to nodes, departments correspond to node-level attributes, and course prerequisites correspond to directed edges. I created the following chord diagram in order to visualize the 2013–2014 WesMaps catalog.
The outer arcs correspond to academic departments or programs. Their colors indicate their academic divisions, which loosely correspond to groupings on WesMaps. The chords within the circle are directed edges between departments—hover your mouse over an edge for more information. Each chord indicates that courses in the source department have prerequisites in the target department. For example, courses in the Economics department have 27 prerequisites in the Mathematics department, as indicated by the green chord between ECON and MATH, and courses in the QAC have 1 prerequisite in the Economics department, as indicated by the red chord between QAC and ECON. The colors of these chords correspond to their source departments.
Note that some departments and programs (such as History) do not appear on this diagram because none of their courses have any prerequisites.
This visualization reveals two interesting observations. The first reflects how the number and arrangement of course prerequisites differs across divisions. The Humanities departments are “horizontal” with few prerequisites overall (because their arcs are narrow) and across departments (because they have few chords). In contrast, the Natural Science departments are “vertical” with many prerequisites overall (because their arcs are wide) and across departments (because they have multiple wide chords). The Social Science departments are mixed—departments like Government and Religion have a pattern similar to the Humanities, while Economics has a pattern similar to the Natural Sciences.
A second observation is that interdisciplinary programs, certificates, and course clusters (the red, purple, and brown arcs, respectively) each have a large number of prerequisites in multiple departments. For example, courses for the Civic Engagement certificate have prerequisites in nine departments. Note that the first observation seems to hold—the College of the Environment, Environmental Studies Program, and certificate in Environmental Studies each have the widest arcs.
Nevertheless, this visualization isn’t perfect. It only reveals prerequisites for courses in a department, not prerequisites for the major. It also fails to capture prerequisites recursively. For instance, a course that requires ECON110 also requires MATH118, MATH122, MATH221, or MATH222, one of which is a prerequisite to ECON 110. Hence the widths of the arcs and chords may be incorrect for some departments. Good extensions would be to perform proper network analysis, and to collect data for different terms in order to study how course prerequisites have changed over time.