Household sampling designs: differences and similarities between probability sampling and route and quota sampling

Abstract

This paper compares the representation quality of three face-toface household surveys. Two of them used probability samples and the other one selected the ultimate sampling units by using random route and quota sampling, with non-responses resulting in ‘automatic’ substitutions. The hypothesis to be tested is that random route sampling and quota sampling (with substitution) provide similar representative quality as home sampling (without substitution) based on the local population register. Marked differences were found in education level in the probability samples, where the deviations exceeded 25%. A different picture emerged when comparing employment variables, where quota sampling overestimated both the labour force participation rate (by 2.5% points) and unemployment rates (9.5% points).