Special Adjustments

Conclusions

In some circumstances, the projection methods described in this book cannot be applied in a simple, straightforward way. Missing or inaccurate data, complicated population dynamics, and unique events sometimes mean that a basic projection model must be adjusted before reasonable projections can be made. In addition, the needs of data users may require that adjustments be made to the resulting projections.

In this chapter, we described several circumstances in which the straightforward application of a projection method might produce inconsistent or misleading results. We then presented a number of procedures for dealing with the problems created by these circumstances. We also described a number of interpolation procedures for creating additional age and temporal detail and for controlling population characteristics from one projection to a total population (or migration) value from another projection. These adjustment procedures will not solve every problem that might be encountered, of course, but they will help the analyst deal with some of the special circumstances affecting the production of state and local population projections.