The Discussion Papers series presents results from ongoing research projects and other research and analysis by SSB staff, intended for international journals or books. The views and conclusions in this document are those of the author(s).
By directly estimating all categories, it avoids residual determination issues, where one category is estimated as the difference between the total population and the sum of others. The multivariate approach improves the accuracy of the population estimates for each category. Additionally, the paper introduces a method to account for time-varying biases associated with how long the respondents have participated in the survey, explicitly incorporating wave-specific effects and their evolution over time.