Factors which do not move readily between sectors, regions, or countries when relative rewards or job opportunities change. Immobility of labour between occupations may be due to lack of qualifications, or to inadequate information on job opportunities. Labour mobility between regions or countries is restricted by social ties, and by housing markets which are often organized so as to favour those who stay put over those who move. Mobility between countries is also hindered by differences of language and social customs, and frequently by legal restrictions. Mobility of capital, while often greater than that of labour, is also limited by lack of information, by differences between countries in law and commercial practices, and in many cases by legal restrictions. See also factor mobility.