This appendix contains eight sections. Section 1 gives technical details of how we calculate standard errors in the CPS data. Section 2 discusses changes in the ACS procedures before 2005. Section 3 examines demographic and economic patterns in migration over the past two decades, in more detail than in the main paper. Section 4 examines the cross-sectional variance of location-occupation interactions in earnings when we define locations by MSAs instead of states. Section 5 describes alternative methods to estimate the variance of location-occupation interactions in income. Section 6 measures the segregation of industries across states and of occupations and industries across MSAs. Section 7 gives technical details on the use of SIPP and census data to calculate repeat and return migration rates. Section 8 discusses transition dynamics in the model.

We analyze the secular decline in interstate migration in the United States between 1991 and 2011. Gross flows of people across states are about 10 times larger than net flows, yet have declined by around 50 percent over the past 20 years. We argue that the fall in migration is due to a decline in the geographic specificity of returns to occupations, together with an increase in workers’ ability to learn about other locations before moving there, through information technology and inexpensive travel. These explanations find support in micro data on the distribution of earnings and occupations across space and on rates of repeat migration. Other explanations, including compositional changes, regional changes, and the rise in real incomes, do not fit the data. We develop a model to formalize the geographic-specificity and information mechanisms and show that a calibrated version is consistent with cross-sectional and time-series patterns of migration, occupations, and incomes. Our mechanisms can explain at least one-third and possibly all of the decline in gross migration since 1991.

In order to analyze careers both within and across firms, this paper proposes a matching model of the labor market that extends existing models of job assignment and learning about workers’ abilities. The model accounts for worker mobility across jobs and firms, for varying degrees of generality of ability, and for the possibility that firms affect the information they acquire about workers through job assignment. I characterize equilibrium assignment and wages, and show how, depending on how abilities and jobs are distributed across firms, equilibrium gives rise to widely varying patterns of job mobility within firms and turnover across firms, even if matching would be perfectly assortative in the absence of uncertainty. The implied job and wage dynamics display features that are consistent with a broad set of empirical findings on careers in firms and the labor market. In particular, workers can experience gradual promotions and wage increases following successful performance but few or no demotions when employed by the same firm. The model also produces turnover across firms and occupations after both successful and unsuccessful experiences, leading to wage increases or decreases following a firm or occupation change. Overall, the results in this paper provide a unified framework in which to interpret the dynamics of jobs and wages in firms and the labor market.