The LISS panel (Longitudinal Internet Studies for the Social sciences) is the principal component of the MESS project. It consists of 5000 households, comprising approximately 7500 individuals. The panel is based on a true probability sample of households drawn from the population register by Statistics Netherlands. Households that could not otherwise participate are provided with a computer and Internet connection. In addition to the LISS panel an Immigrant panel was available from October 2010 up until December 2014. This Immigrant panel consisted of around 1,600 households (2,400 individuals) of which 1,100 households (1,700 individuals) were of non-Dutch origin. The data from this panel are still available through the LISS data archive (https://www.dataarchive.lissdata.nl/study_units/view/162).
Panel members complete online questionnaires every month of about 15 to 30 minutes in total. They are paid for each completed questionnaire. One member in the household provides the household data and updates this information at regular time intervals.