Collect data at the beginning of the year on the number of students who enroll at a school for that academic year. For example, if 100 students sign up for a particular school at the beginning of academic year 2009, the number of students in the incoming class of 2009 is 100.
Collect data the following year on the number of students from your sample in Step 1 who are still enrolled at the school. For example, if in Step 1 you noted the number of students enrolled from the incoming class of 2009 during academic year 2009, Step 2 requires you to note the number of students from the incoming class of 2009 class who are still enrolled during academic year 2010.
Divide the number calculated in Step 2 by the number of Step 1. For example, 90 (Step 2) ÷ 100 (Step 1) = 0.9 or 90 percent. The result of this calculation is the student retention rate. Ninety percent of students of the incoming class of 2009 remained at the school after one year.