What drives the geography of jobs in the US? Unpacking relatedness

There is ample evidence of regions diversifying in new occupations that are related to pre-existing activities in the region. However, it is still poorly understood through which mechanisms related diversification operates. To unpack relatedness, we distinguish between three mechanisms: complementarity (interdependent tasks), similarity (sharing similar skills) and local synergy (based on pure co-location). We propose a measure for each of these relatedness dimensions and assess their impact on the evolution of the occupational structure of 389 US Metropolitan Statistical Areas (MSA) for the period 2005–2016. Our findings show that new jobs appearing in MSA’s are related to existing ones, while those more likely to disappear are more unrelated to a city’s jobs’ portfolio. We found that all three relatedness dimensions matter, but local synergy shows the largest impact on entry and exit of jobs in US cities, thus being the strongest force of diversification.