Abstract: Focusing on the data of ethnic and religious identities in a multiethnic and multicultural context, this paper provides research-based evidence to explain whether and how significantly such data could be reliable from a social and demographic perspective. The explanation is based on population census that also provides unique nation-wide data sources on ‘religious affiliation’. The field of this study is the multiethnic and multicultural context of Australia that holds a large variety of ethnic, religious and cultural groups from throughout the world. According to the findings of the present analysis, this paper argues that if ethnic migrants belonging to the same category of religious affiliation are considered as a single group without taking their ethnic origins into account, this will lead to insufficient, incomplete, and misleading knowledge.
