I don't know what the state of the art is, but in the 2010s there was a huge mess where a 'biographical evaluation' test was required of ATC applicants, with the timing such that you took it after the FAA prep courses. The evaluation was thinly veiled racism, utterly uncorrelated with ATC performance, and one of the big outcomes was that anyone taking the prep courses was very likely to get weeded out by the biographical evaluation and thus suffer a total loss of his time and financial investment in the course.

So ,that was another problem they were causing themselves in manning.

Edited to add documentation: https://kaisoapbox.github.io/projects/faa_biographical_asses...