Most long-term moves are likely because the move provides a higher level of well-being through improved job opportunities and/or higher wages. Well-being might also be improved if the move offers an increase in quality of life, better schools, less crime, or better weather (Roback, 1982). As well, the relative productivity of traditional activity in different places will affect the pattern of migration. The net migration rate of a particular place is calculated by dividing net migration by the population of the place at the beginning of the period.