Medical education is all about competency. At the end of training, you want to be assured that you’ve released a competent professional into society. That doesn’t mean, however, that medical education is always competency-based — in fact, the Flexner-style of medical education is distinctly time-based.

But that’s changing. Many experts in the field, including AAMC President and CEO Darrell Kirch, the folks at CanMEDS, and many innovative programs are pushing the field towards competency-based education.  

The push towards competency-based education will require new assessments, and new approaches to analyzing assessment results. One format that we’ve seen quite a bit is the spider graph.

What is a Spider Graph?

Spider graphs are also known as spider charts, radar plots, or competency reports. Each axis of the graph represents one of the competencies you are interested in measuring, for example, CanMEDs roles or ACGME competencies. The scale on each axis represents the level of that competency. One common scale used to represent the level of competency is the Dreyfus model of skill acquisition: Novice, Advanced Beginner, Competent, Proficient, and Expert. The “web” of lines that links the axes shows how the person rates on each competency.

This type of visual competency report is used by many of our undergraduate (UGME) medical school clients. These clients like spider graphs because they can base their assessments off of competencies and use the spider graphs to compare how students are performing against the school’s competencies.

Pros and Cons

By design, spider graphs can help identify outliers. Students who perform well above or below the group average will easily stand out. For students who are particularly strong in one area, you might observe a “balloon out” pattern, and for students who are underperforming in one area, you will see a “cave in” pattern. In cases of under-performing students, spider graphs can be used to facilitate discussions and to show them how they are doing in comparison to their peers.

Here’s an example of a typical 3rd Year Clerkship student’s Spider Graph, as generated by the one45 system:

As you can imagine, the vast majority of the thousands of spider graphs we see from our clients look fairly similar. Most of them are round webs showing average performance. While spider graphs are great at highlighting obvious deficiencies, subtle issues are often hidden under the weight of average ratings, rater issues, and the inevitable simplification that occurs when you lump a multifaceted competency such as Professionalism into one general rating.

Additionally, while spider graphs are useful for comparing one individual’s performance against a standard or group’s performance, they are not so useful once you have more than two webs, or if you have many axes. For that reason, spider graphs should be considered and used judiciously – or not at all.

For a more in-depth look at some disadvantages of spider graphs, the article A Critique of Radar Charts is a useful read. If you’re interested in learning how to create your own spider graphs, check out our best practices guide on How to Visually Represent Competency: Spider Graphs & Radar Plots.