The Introduction of Bias in Birth Projections in Small Areas near Colleges and Universities: Impacts and Adjustments

David Gagnon, National Perinatal Information Center
Janet Muri, National Perinatal Information Center

A central concern in the preparation of birth projections for small geographical areas near college level educational institutions is the potential bias introduced by the presence of a sizable population of females in the prime reproductive years who are actively deferring fertility behavior. This concern is increased when birth projections are created for the purposes of guided policy development among city planner and hospitals as these groups are typically interested in projections for very small geographic areas, often as small as a zip code or a set of census tracts. This paper reviews work performed by the authors to develop realistic birth projections for a city with six local colleges and universities within its projection geography. The paper reviews the methodological challenges faced in the development of birth projections in geographies with high proportions of fecund females but low rates of reported fertility and ways to adjust for this bias.