Estimating the prevalence of children living with a stepparent in New Zealand using linked administrative, census, and survey data

Robust estimates of the incidence of children living with a stepparent are lacking, partly due to a lack of the requisite questions on census and survey questionnaires. Even when these questions are included, resultant estimates are impacted by how respondents choose to portray their relationships. Our first aim was to develop a method for combining census or survey data with administrative data (birth registrations and migrant visa applications) to identify step-relationships. Our second aim was to use this methodology to calculate estimates of children living with a stepparent in New Zealand. We estimate 7.5% of children aged 17 and under were living with a stepparent at the 2013 Census. Estimates using Household Labour Force Survey data produced slightly lower estimates of 6.3-6.9% of all children aged 17 and under for the years 2016 through 2019. Our results provide the most comprehensive attempt to estimate the prevalence of children living with stepparents in New Zealand to date, and demonstrate a novel methodology for identifying step-relationships using administrative data in a linked data environment.