The first [reason] is that the mix of jobs offered in different parts of America has become more uniform. The authors compute an index of occupational segregation, which compares the composition of employment in individual places with the national profile. Over time, their figures show, employment in individual markets has come to resemble more closely that in the nation as a whole.
This homogenisation reflects the rising importance of “non-tradable” work…
Yet a more uniform job distribution alone cannot account for falling mobility. As Messrs Kaplan and Schulhofer-Wohl point out, mobility has fallen for manufacturers, where jobs are more dispersed, as well as for service-sector workers. What is more, if workers know that they can find jobs they want in different places, they may become more willing to move for other reasons—to be by the coast, for example, or to savour a particular music scene. Yet survey data reveal that moves for these other reasons have not risen. The authors suggest another force is also reducing migration: the plummeting cost of information.
…In recent decades, however, it has become much easier to learn about places without moving house. Deregulated airlines and innovative online-travel services have slashed travel costs, allowing people to visit and assess different markets without moving. The web makes it vastly easier to study every aspect of a potential new home, from the quality of its apartment stock to the surliness of its baristas, all without leaving home. Falling mobility isn’t simply caused by labour-market homogenisation, the authors argue, but also by greater efficiency. People are able to find the right job in the ideal city in fewer hops than before.