Unlike the USMLE, they re-scale the COMLEX every 4-5 years so that a 500 is the new average. So if you keep getting smarter students, the COMLEX keeps getting harder, unlike the USMLE, where scores keep slowly ticking up and the bar to fail moves with it.
The problem with this is that many residencies set their COMLEX score at the 50th-75th percentile, while their USMLE scores are at the 15th percentile- I was looking at one program that had a minimum 200 for the USMLE and a 540 for the COMLEX, for instance. Depending on how they set their cutoffs, that means we have to hit both, which really hurts us given the recent recalibration- a 200 on the USMLE is easy AF to get, but a 540 COMLEX means I'm going to have to spend way more time with Savarese than I'd like, which detracts from my USMLE.