Country of birth of parent 1/mother (BPP1P)

This variable indicates the country in which a person’s parent 1 was born. This is likely to be their mother as that is suggested in the question wording; however, it could be a parent of any gender, or relation (for example, step parent or adopted parent). 

All persons 

Country of birth of parent 1/mother is coded using the Standard Australian Classification of Countries (SACC), 2016.  

Number of categories:  

• one-digit: 12 
• two-digit: 39 
• four-digit: 293 

See Understanding supplementary codes for more information.    

Country of birth of parent 1/mother (BPP1P) is a person-level variable derived from the response to the country of birth of the person’s mother or parent 1 question on the Census form. 

Most responses are coded automatically from mark box fields. Manual coding processes are applied where auto-coding is not possible.   

All coding processes follow the rules below: 

• Former country names are coded to the current country name (for example, ‘Siam’ is coded to ‘Thailand’) 
• Where more than one response is provided (for example, the respondent selects ‘Australia’ and also writes ‘Thailand’), responses are accepted in the order they appear on the form and additional responses are rejected. In this example, the response would be coded as ‘Australia’ 
• BPP1P is coded using the 2016 version of the SACC. Where a response is not listed in the classification, it is coded as ‘Inadequately described’ 

If no response is provided to the country of birth of mother or parent 1 question, BPP1P is coded as ‘Not stated’. Where a respondent did not provide their parent's county of birth, statistical processes will be used to determine if this question can be answered using the parent's response to the country of birth question (BPLP), if they were staying in the same household on Census night. 

A question relating to the country of birth of a person’s mother was first asked in the 1921 Census. This question was not included again until the 1971 Census and has been included in every Australian Census since. Data from this question was released under the variable name country of birth of mother (BPFP). 

Significant changes were made to the question wording in the 2026 Census. As a result, data may not be fully comparable with previous Censuses.  

The question wording was updated to be more inclusive of gender diverse parents, adoptive, and step parents. This included updated terminology in the question text on the online form, as well as revised instructional text across all form types. Consequently, the variable name and definition were updated to also refer generically to a ‘parent’, rather than specifically to ‘mother’ or ‘father’. 

The order of questions about the country of birth of parents has also changed since the previous Census. Country of birth of mother or parent 1 is now asked before country of birth of father or parent 2.