Stepwise Proportional Weighting Algorithm for Single-Race Population Estimation Using Hawai'i Census Data.

Many health and health disparities studies require population prevalence information of various race groups, but the estimation of single-race population sizes using the US Census data has been challenging. For each Census race group, Census only provides the counts of those reported being single race ("race alone") and those reported of that specific race regardless of whether the individuals were multiracial or not ("race alone or in (any) combination"). The issue of how to classify Census multiracial individuals is especially important for the state of Hawai'i due to its large multiracial population. The current study developed the Stepwise Proportional Weighting Algorithm (SPWA) for single-race population estimation using US Census data for major race groups in the Census and their nested detailed races. Additionally, given that "partial Native Hawaiian" has often been treated as "Native Hawaiian" in health disparities studies in Hawai'i, the algorithm can also adjust for the unique partial Native Hawaiian race categorization. This paper describes the estimation process with the SPWA and demonstrates its ability to estimate single-races for the 5 most common race groups in Hawai'i. This new methodology addresses an important concern regarding how to classify multiracial individuals to strengthen health and health disparities research in Hawai'i.