A Bayesian Projection of the Total Fertility Rate of Puerto Rico: 2020-2050

TL;DR

This paper presents a Bayesian projection model for Puerto Rico's Total Fertility Rate (TFR) from 2020 to 2050, suggesting a potential TFR of around 1.1 and a significant population decline, challenging existing optimistic projections.

Contribution

It introduces a modified Bayesian fertility projection model tailored to Puerto Rico, accounting for low fertility levels without assuming a return to replacement fertility.

Findings

Projected TFR of 1.1 by 2050 with credible interval (0.56,1.77)

Indicates a larger population decline than current projections suggest

Challenges the assumption of fertility rebound to 2.1 in low-fertility contexts

Abstract

The abrupt decline in the Total Fertility Rate (TFR) of Puerto Rico since 2000 makes the prospect of a sustained population decline a real possibility. From 2000 to 2021 the TFR declined from 2.1 to 0.9 children per woman, one of the lowest in the world. Population projections produced by the United States Census Bureau and the United Nations Population Division show that the island population may decline from 3.8 millions in 2000 to slightly above 2 million by 2050, a dramatic 47% population decline in 50 years. As dire as this prospect may be, this may be an optimistic scenario. Both projections have the TFR increasing to 1.5 by 2050, but a fertility projection conducted by us show that fertility can remain much closer to 1.0 until 2050. Bayesian Hierarchical Probabilistic Theory has been used by the United Nations to incorporate a way to measure the uncertainty and to estimate the projection parameters. However, the assumption that the fertility level in countries with low fertility will eventually increase to 2.1 has been widely criticized as unrealistic and not supported by evidence. We modified the assumptions used by the United Nations considering countries with TFR similar to Puerto Rico and find that by 2050 Puerto Rico may have a TFR of 1.1 bounded by a 95% credibility interval (0.56,1.77). This indicates that there may be a larger population decline than what current projections show.