"I examine the determinants of inter-state migration of adults within western Germany, using the German Socio-Economic Panel from 1984-2000. I highlight the prevalence and distinctive characteristics of migrants who do not change employers. Same-employer migrants represent one fifth of all migrants higher education and pre-move wages than non-migrants. Conditional on age, same-employer migrants are therefore more skilled than non-migrants. By contrast, although other migrants have higher education than non-migrants, they do not have higher pre-move wages. Furthermore, they have in their ranks disproportionate numbers of the non-employed, unemployed and recently laid off. It therefore seems inappropriate to characterize them as more skilled than non-migrants. The results for same-employer migrants indicate that skilled workers have a low-cost migration avenue that has not been considered in the previous literature. I also analyze the relation between repeat and return migration and distinguish between short and long-distance migration. I confirm that long-distance migrants are more skilled than short-distance migrants, as predicted by theory, and I show that return migrants are a mix of successes and failures"--National Bureau of Economic Research web site.