Lee's model of migration proposes that people move due to push and pull factors. Push factors induce people to leave their origin location due to negatives like poverty or instability, while pull factors attract people to destinations that have positives like job opportunities or thriving economies. People evaluate the push and pull factors of different locations along with any intervening obstacles like distance or borders to determine if the factors are strong enough to force or entice migration, or if closer intermediate locations are preferable.