Atlanta showed a 51.89% increase in heavy rail passengers. This is essentially all due to changing counting methodology.
The old method used fare gates, but some were broken or bypassed. The new method was human counts in person and by video with sampling and extrapolations. Next they'll switch to new fare gates and count the old way.
A 52% increase based on methodology?! This highlights how far off the APTA numbers can be, even when the agencies fill out the forms correctly. (When they don't, the numbers can be off far more.)
This is why ACS commute stats are a key data point. While they only count commutes, at least they used the same methods so everything is parallel.
https://www.youtube.com/watch?v=sHIhxdd9BwA