Changes

The most important push factor is difficulty in making a good living at home.  In an agricultural society, there may be a shortage of land and a surplus of workers, so that over time either the farms become smaller, or the excess population leaves agriculture.  In an urban society if there is stagnation in industry, unemployment results unless people leave.  In any given place, some people will be strongly rooted and others will be more eager to move on.  For example, eldest sons who are in line to inherit the family farm would be more rooted than younger sons with poor prospects of ever owning land.  Workers unhappy with their jobs or pessimistic about future prospects would be more willing to consider a move to improve their possibilities.  

The most important push factor is difficulty in making a good living at home.  In an agricultural society, there may be a shortage of land and a surplus of workers, so that over time either the farms become smaller, or the excess population leaves agriculture.  In an urban society if there is stagnation in industry, unemployment results unless people leave.  In any given place, some people will be strongly rooted and others will be more eager to move on.  For example, eldest sons who are in line to inherit the family farm would be more rooted than younger sons with poor prospects of ever owning land.  Workers unhappy with their jobs or pessimistic about future prospects would be more willing to consider a move to improve their possibilities.  

Other push factors include religious or ethnic persecution, or the threat of war, famine or other disaster, or a general pessimism and malaise about the future.

Other push factors include religious or ethnic persecution, or the threat of war, famine or other disaster, or a general pessimism and [[malaise]] about the future.

Pull factors are attractions that exist in the destination, especially freedom to achieve and prosper.  The psychological conviction that life will be better at the destination is a powerful pull factor, reinforced by images in the media, and especially by optimistic letters home from successful immigrants and cash remittances. The most important attractions are good jobs,  (especially in the 19th century) land for farming, and a sense that the new land offers more freedom and opportunity.

Pull factors are attractions that exist in the destination, especially freedom to achieve and prosper.  The psychological conviction that life will be better at the destination is a powerful pull factor, reinforced by images in the media, and especially by optimistic letters home from successful immigrants and cash remittances. The most important attractions are good jobs,  (especially in the 19th century) land for farming, and a sense that the new land offers more freedom and opportunity.

The decision can be analyzed though a cost-benefit analysis of the push and pull factors. If a person judges the pull and push factors outweigh the cost or disadvantages of moving the that person is likely to move.  If the costs outweigh the pull and push factors, the person is not likely to move.  Furthermore, it takes time to move; many people stay around to build up cash reserves or gain educational credentials. However, even when someone decides to move intervening obstacles play a role. Long distances, the expense of moving, poor health, fears about the drastic changes in a far-off land, and family obligations may induce a person who wants to move to stay home.

The decision can be analyzed though a cost-benefit analysis of the push and pull factors. If a person judges the pull and push factors outweigh the cost or disadvantages of moving the that person is likely to move.  If the costs outweigh the pull and push factors, the person is not likely to move.  Furthermore, it takes time to move; many people stay around to build up cash reserves or gain educational credentials. However, even when someone decides to move intervening obstacles play a role. Long distances, the expense of moving, poor health, fears about the drastic changes in a far-off land, and family obligations may induce a person who wants to move to stay home.

===Selectivity===

===Selectivity===