Muslim women wearing face-covering clothing are the subject of politically
heated debates in a number of European countries, but reliable data on the number of these women (niqabis) are generally lacking. At the request of the Danish government, the authors conducted a survey of niqabis in Denmark; this work is the first attempt to quantify niqabis in a European country by sampling new data from several different kinds of sources. Sociologically, niqabis represent a rare and elusive group, which presents particular methodological challenges. The methods discussed and used, such as stratified sampling, use of key informants, and location sampling, are relevant in the studies of many contemporary religious sub-cultures. Extensive triangulation of the
different data provided an estimated number of niqabis of 150, with an uncertainty range of 100–200. This corresponds to 0.1–0.2% of Muslim women in Denmark. These figures tally with current rough estimates in other European countries.