Blog Post

Fertility Insight: Utah's population is not just homegrown

By: Dr. Pamela Perlich, Ph.D.

The population of Utah recently surpassed 3 million. This milestone has been achieved as a result of the combination of positive natural increase, with the annual number births consistently exceeding deaths, and significant net in-migration, especially since 1990. People who follow population issues in Utah are well aware of the state’s signature demographics, which include the highest fertility rate and youngest median age among all states. It was quite fitting that Governor Herbert recognized this milestone while standing in a maternity ward. 

If we do the math on annual components of population change, natural increase accounts for about two-thirds of the Utah population growth since the 2 million mark that occurred in 1995. The other third is net in-migration, which is gross in-migration minus gross out-migration. But this annual accounting does not adequately recognize the full extent of the contribution of new migrants to Utah’s population growth. Let me explain.

Data definitively demonstrates that young adults are the most likely to migrate, often in search of economic and educational opportunities as well as adventure. Once established in their new residences, they form households and often have kids. Fertility also, and not coincidentally, peaks in early adulthood. These new young adult residents and their offspring contribute to the growth and also the youthfulness of the population. This multigenerational impact is often overlooked in standard decompositions of Utah’s population growth. The mirror image of this dynamic is experienced in places of economic decline when young people move away leaving an aging and declining population.

Beyond Fertility: Utah's population is not just homegrown

Today, we are releasing a paper that explores this issue in some detail: “Migrant Today, Parent Tomorrow: A Zero Migration Simulation.” We used a simplified population projection model to create an alternative past where no migration to or from Utah occurs, beginning in 1990.  This zero migration scenario captures this multigenerational demographic impact and definitively shows that “homegrown” population alone would not get Utah to the 3 million mark for almost another generation. This alternative past demonstrates that, in the absence of the considerable in migration of young adults to Utah, and their progeny, the population of Utah would not reach the 3 million milestone for another 15 years! Incidentally, current projections for Utah indicate that the state is expected to reach its next million milestone of 4 million the same year: 2031.

What we illustrate in this work is that common interpretations of Utah’s population growth, especially since 1990, do not adequately credit migration as a source of growth. The 2015 population of Utah would be 2.5 million, not 3 million, in the absence this migration. This means that half, not a third, of the most recent one million new Utahns, are here because of people moving to the state since 1990. Without this migration, median age would be older and the share of children in the population would be smaller. Today’s migrants often become tomorrow’s parents.

Dr. Pamela Perlich is the director of demographic research at the Kem C. Gardner Policy Institute.