“…Our b a s i c model regards a person ( o r family) a s migrating i n t h e "Many s t u d i e s of r e t u r n migration (Bowman and Myers, 1967;DaVanzo, 1976;Kau and Sirmans, 1976;Yezer and Thurston, 1976;Long and Hansen, 1977a and b;M i l l e r , 1977;and Allen, 1979) use aggregate U.S. Census d a t a , which measure r e t u r n and o t h e r repeat migration by comparing a p e r s o n ' s p l a c e s of residence a t (1) t h e time of t h e census, ( 2 ) f i v e years b e f o r e t h e census, and ( 3 ) b i r t h . e x p e c t a t i o n of b e i n g b e t t e r o f f by doing s o ; i .…”