1. Lee’s Migration Model

2. Simple Migration Model

3. Simple Migration Model
Location A

4. Simple Migration Model
Location A

5. Simple Migration Model
Location A Location B

6. Simple Migration Model
Location A Location B
Push

7. Simple Migration Model
Location A Location B
Push Pull

8. Lee’s Migration Model

9. Lee’s Migration Model
Location A

10. Lee’s Migration Model
Location A Location B

11. Lee’s Migration Model
Location A Location B
+ -
0

12. Lee’s Migration Model
Location A Location B
+ - + -
0 0

13. Lee’s Migration Model
Location A Location B
+ - + -
0 0

14. Lee’s Migration Model
Location A Location B
+ - + -
0 0

15. Lee’s Migration Model
Location A Location B
Intervening Obstacles
+ - + -
0 0

16. Lee’s Migration Model
Location A Location B
Intervening Obstacles
+ - + -
0 0

17. Lee’s Migration Model
Location A Location B
Intervening Obstacles
+ - + -
0 Intervening Place 0

18. Lee’s Migration Model
Location A Location B
Intervening Obstacles
+ - + -
0 Intervening Place 0
+ -
0

19. Lee’s Migration Model
Location A Location B
Intervening Obstacles
+ - + -
0 Intervening Place 0
?
+ -
0

20. Lee’s Migration Model
Location A Location B
Intervening Obstacles
+ - + -
0 Intervening Place 0
?
+ -
0
Source: Adapted from Global Challenge. Alistair McNaught and Michael Witherick. Longman. 2001.