Methods of Enrollment Projection

There are two commonly used methods for projections at the local level; Grade Progression Rations and Cohort Component Method. Often both methods are run and an 'amalgam' of both taken for a final projection, since each has certain advantages over other methods.

Grade Specific Enrollment Projection using Grade Progression Ratios (GPR)

Using this method, an historical baseline, usually five years, is established and projected forwarded for an additional five years. Although migration is not explicitly factored in, having ratios greater than one (1) account, in part, for this aspect. Entering kindergartners are computed as a ratio of district wide births (five years earlier and adjusted for the school year) and the historic proportion of students entering school five years later.

Cohort Component Method (CCM)

This method looks at each cohort (age group, usually five year intervals) and determines the impact of each of the demographic components (births, deaths, and migration) on that cohort through the projection period. It is computed by:

Ef = Ec + B - D + NM

In other words, Future Enrollment (Ef) is equal to Current Enrollment (Ec) plus Births (B) minus Deaths (D) plus Net Migration (NM).

Net migration, since it is often not available at the local level, can be calculated using Residual Net Migration (RNM) derived from the Forward Survival Method (FSM). The FSM projects migration to the end of the projection period (given historic rates of migration) and interpolates for intermediate years.

A Graphical Comparison

GPR	CCM

© 2003 Spatial Analytics, Inc.