This is one of a series of papers written for the Review of the Measurement of Ethnicity,undertaken by Statistics New Zealand. It outlines the multitude of ways that countries collectinformation about ethnicity and related variables.Ethnicity is a variable that is collected to enable groups of like people to be defined andmeasured, and to analyse social and cultural characteristics within a population. On the macrolevel, ethnicity grouping allows analysis of the population in the fields of education, employment,health status, morbidity and mortality, and many other variables. Differences found betweengroups have an impact on policy and placement of resources.There are differences between countries in how information on ethnic groups is collected and inthe number of questions asked to define the groups. This relates to the particular history,politics, religion and social dynamics within individual countries.Different countries collect statistics on one or more of these variables: nationality, ethnic group,race, citizenship, immigrant status, country of birth, language, religion and ancestry. Somecountries are aware of the need to have a practical definition of ethnicity and devise questionsthat relate to that definition. The definitions of these variables may differ from New Zealand use.Therefore data collected may be meaningful in one country, but not necessarily able to providethe information needed in another. For example, the United Kingdom uses the term ethnic groupin its 2001 Census but asks respondents to give an answer based on colour. New Zealandcollects a self-perceived ethnic group affiliation, language, country of birth, plus an ancestryquestion for Mäori.