Decomposing adolescent birth rates in the U.S.: Contributions of individual states and population subgroups to the nationwide decline

The adolescent birthrate (ABR, births per 1,000 females aged 15-19) has dropped substantially in the U.S. since the 1990s.  While there are a number of factors (e.g., public policies, social, cultural and economic factors) contributing to the decline, we focus on the contribution of individual states and population subgroups to the ABR decline.

To determine the contribution of each state to the nationwide ABR decline, we used nationally available birth and population data between 1991 and 2011 and applied a decomposition method published by the U.S. Census Bureau.  This method breaks down the total change over time in a rate relative to the population change and attributes it to the individual states.

The results show that changes in birth patterns among the top ten states with the largest number of adolescent births contributed 57% to the ABR nationwide decline between 1991 and 2011.  Of the top ten states, California contributed 16% to the decline while the remaining nine states’ contribution ranged from 3% to 6%.  California’s contribution is substantial given California represented 12% of adolescent births in the U.S. in 2011.  In contrast, Texas, a state that closely resembles California’s population composition represented 13% of adolescent births and contributed 6% to the national decline.

Examining the compositional and rate effects in the ABR decline will be used to identify the relative contribution of age and racial/ethnic population subgroups.  This information can subsequently facilitate tailoring specific services amenable to specific subgroups to help narrow the considerable disparity in ABR nationwide.