Since 1996, reports on cohabiting same-sex partnerships have been collected in the German Microcensus. However, it is unclear how reliable these reports are. Compared with other data sources, the Microcensus shows only a small number of cohabiting same-sex couples (less than 0.5% of all cohabiting couples in 2016), so under-reporting is assumed. But, because the "true" values are unknown, it is difficult to determine whether under-reporting is actually occurring. In this paper a procedure is proposed where the response behaviour of respondents is analysed depending on the composition of their household. It was found that non-response to the question about a partner in the household is highest among respondents in whose household there is a possible same-sex partner. This indicates under-reporting of cohabiting same-sex couples, and this under-reporting decreased only slightly, at most, over the period considered here (1996 to 2016). This is not the case for registered same-sex partnerships: a comparison with the Census shows that these are reliably recorded in the German Microcensus.

GESIS Papers, 2022/01, 29 S.