This was a tough one to figure out. On our length of stay report you enter in a date range. The system then determines, from everyone who moved out during that time period, how many days each of them stayed there. It takes this total # of days, divides it by how many people moved out. That number is then divided by 365 to get the turnover. Reverse that last calculation to get the average length of stay. Whew. You asked... :P