Significant progress has been made addressing adolescent health needs in New Zealand, but monitoring and gathering high quality estimates of adolescent health and social issues remains challenging and resource intensive. Previous nationally representative secondary school surveys were conducted in New Zealand in 2001, 2007 and 2012, as part of the Youth2000 survey series. This paper focuses on a fourth survey conducted in 2019 (https://www.youth19.ac.nz/). The 2019 survey had a regional sampling strategy rather than a national sampling strategy as in previous years. The survey also included kura kaupapa Māori schools (Māori language immersion schools), as well as mainstream secondary schools. This paper presents the overall study methodology, and a weighting and calibration framework in order to provide estimates that reflect the national student population, and enable comparisons with the previous surveys to monitor trends.