PM
The number given in the study for Yeshiva schools over five years is a little over 14%. This comes out to a growth rate of about 2.7%.
I calculated the growth rate numbers by comparing the # of first graders with the number of 12th graders. Ff done that way the growth rate comes out to about 3.2% in this study and if my memory serves me right a little more in the previous one.
I do not think the numbers obtained by comparing the studies is completely accurate. When one compares the numbers of children the same class (eg 1st grade in the ’00 and 6th in the ’05) between the two studies the numbers are off by about 1% one way or the other. For this reason I think a more acurate picture is obtained my comparing the grades in the same study.
Another factor that may cause the growth rate to be underestimated when using school data is the fact that very small schools with only a few grades are more likely to be missed. These shools would be expected to have the highest population growth as they are composed of the youngest families.