Birth Rate Hogwash

Written by Dave Gardner on October 2, 2008. Posted in Blog

Gazette reporter Perry Swanson invested considerable time into trying to understand why I discount growth boosters’ preoccupation with using “net natural increase” and “net migration” figures to give the impression fertility is the biggest contributor to our burgeoning local population. So it surprised and disappointed me to see a gross figure, birth rate, compared with net migration in both a caption and his story (Look how we’ve grown, 3/16/06). That’s the kind of manipulation of data I’ve come to expect from the growth industry.

One might wonder if there’s something in our water making us much more fertile than the rest of the country. The fertility rate in the U.S. today is just barely above replacement level, so it defies logic that birth rate would be the biggest contributor to our rapidly growing El Paso County population. Part of the explanation is we have many young military families of child-bearing age. Our state demographer has confirmed most of those babies leave the county within a year or two of their birth.

The more usual data spin, subtracting deaths from births and out-migration from in-migration, is nothing more than an academic exercise. In any given year, a large number of those moving out of the county were born here. And only a small number of those who die here were also born here. So it means very little to do the “net natural increase” and net migration” calculations. If one wants to know what is making our population grow, the meaningful figures to examine are those that add to our population: births, and in-migration. According to IRS migration tables, typically over 40,000 people move into our county every year, while fewer than 10,000 are born here. During the years 1994 – 2001, the last years for which this data is available at no charge, in-migration’s contribution to our population increase ranged from 83% to 86% (see chart).

Dave Gardner
Founder & Chair
SaveTheSprings

sources:
http://dola.colorado.gov/demog/irsmig1.cfm
http://dola.colorado.gov/demog/ccinput1.cfm

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