Study and article by the ZEW and the University of Basel concerning the Gender Wage Gap
The ZEW (Centre for European Economic Research, Mannheim), in cooperation with the University of Basel, has published a study on “Gender norms and income misreporting within households” accompanied by an article called “Paare verfälschen Anteil von Frauen am gemeinsamen Einkommen” (Couples distort the share of women in joint income). This study, that is mainly based on the Swiss Labour Force Survey (SLFS), comes to the conclusion that some members of households in which the woman earns more than the man tend to underestimate the woman’s income or to overestimate the man’s income. The authors indicate that this response behaviour could bias statistics on the gender wage gap.
This conclusion does not apply to the results published in Switzerland by the Federal Statistical Office: the data that are officially used to measure the gender wage gap are taken from the Swiss Earnings Structure Survey (ESS) for which information is directly supplied by enterprises.
As regards the SLFS, it should be stressed that it is not the income from employment surveyed in the basic questionnaire that is being called into question but only the income indicated for the partner. The latter is only surveyed every 3 to 4 years in the SLFS as part of the social security module with the aim of providing contextual information.
Finally, as regards the Statistics on Income and Living Conditions (SILC), the income from employment stated by respondents is taken from the Central Compensation Office (income subject to OASI contributions), which means it is possible to exclude any bias in the construction of the total household income.
Neuchâtel, 18 February 2020