There are, in principle, two ways to collect information about visitors of museums: either by population surveys or by visitor surveys also called visitor studies. Population surveys seek to find out which part of the general population visits museums (and subsequently which part doesn't visit) and to discern the demographic characteristics of the visitors, such as gender, age, education level or income. Visitor surveys are conducted among the visitors of a permanent or temporary exhibition of particular museums and usually include demographics, museum visit related behaviour and exhibition satisfaction ratings.