Originally Posted by dotdash
Your point may be valid, but the numbers don't work that way. You have to take the attrition out of the whole working pool, not just the first years.
Then you must add attrition for all the resident years as well. If you want to calculate this accurately without estimates, you take the pgy-1s of a year, and count the dropouts from this group over all their years working as residents. That is your attrition rate for their resident period.
The annual snapshot would be how exPCM did it, he just says that the dropout rates of an average resident year is the same as the dropout rate of the other residents, when they were in this resident year.