Demographic discrepancies between administrative-prioritisation and self-prioritisation of multiple ethnic identifications.

Ethnic classification is an inherently subjective process, especially when multiple ethnic identifications are involved. There are two methods commonly used to classify multiple ethnicities into single categories: administrative-prioritisation (assignment via a predetermined hierarchy) and self-prioritisation (where individuals select their "main" ethnicity). Currently, little is known about whether the demographic composition of outputted ethnic groups differs by prioritisation method. This study utilised large-scale data of multi-ethnic children (N = 1,860), adolescents (N = 2,413), and adults (N = 1,056) from Aotearoa New Zealand to examine individual and contextual demographic characteristics associated with discrepancies between administratively-prioritised and self-prioritised ethnicity. Results showed that discrepancy rates, which exceeded 50%, were systematically associated with neighbourhood ethnic composition and socioeconomic deprivation, but largely not associated with gender, age, and birthplace. The contextual nature of self-prioritisation highlights the importance of researchers' choice of ethnic classification method. Implications are discussed in the context of increasing multi-ethnic prevalence.