Yarger J, et al. - In order to define community-level factors related to the drop in the adolescent birth rate (ABR) in California from 2000 to 2014, researchers undertook this investigation wherein they combined various data sources at the level of the Medical Service Study Area (MSSA), a federally recognized subcounty geographic unit (N = 497). A greater ABR drop was documented in urban vs rural MSSAs. In the earlier period, the factors related to smaller declines in the ABR included growth in the black, Hispanic, and foreign-born populations, unemployment, and receipt of public assistance. Larger reductions in the ABR were evident in relation to growth in the share of married households and high school completion. In the later period, smaller declines in the ABR related to growth in public assistance receipt and larger declines related to growth in high school completion and college attendance were revealed. Programs and policies that are more responsive to the communities they serve are encouraged by knowing the independent contributions of alterations in sociodemographic, economic, and service features to changes in the ABR.