Measuring labour force participation during pandemics and methodological changes

In 2020-2021, several methodological changes were introduced in the Labour Force Survey (LFS), which caused disruptions in data analysis and inference: the Covid-19 pandemic forced a change in the data collection method, and from the beginning of 2021, planned changes related to the harmonisation of social surveys in the EU were introduced (changes in the subject and object coverage of the survey). The aim of this paper is to examine the impact of the methodological changes on the measurement of labour force participation in Poland. Based on the analysis of quarterly LFS data over the period Q1 2019 - Q4 2021, it is shown that the change in the recruitment and interviewing method to CATI and the change in the rotation scheme had a significant impact on survey selection, attrition, propensity to participate in person and thus also on the sample structure, and that the problems of survey selection are not fully compensated for in the process of generalising the results from the sample to the general population. By treating the change in survey method as a natural experiment, it has been shown that the method of recruitment affects the underlying results of the survey. Over the period Q3 2020 - Q3 2021, the changes introduced to the LFS together increased the estimates of the participation rate by around 0.6 percentage points, the employment rate by around 0.1 percentage points and the unemployment rate by around 0.9 percentage points relative to the pre-pandemic measures. If the effect of the inconsistent classification of some people as working in subsistence agriculture is also taken into account, the overestimation of the participation rate under the new methodology would be around 0.9 percentage points.