Census categories for mixed race and mixed ethnicity: impacts on data collection and analysis in the US, UK and NZ

- The census mixed race/ethnicity classification systems in the US, UK and NZ are reviewed.
- These systems have limited success for monitoring mixed populations' health.
- Obstacles to successful use are data input problems and data output problems.
- Data input problems include recording practices and fluidity of self-identification.
- Data output problems include data 'prioritization' and non-publication of data.