Technological diversification of US cities during the great historical crises

Regional resilience is high on the scientific and policy agenda. An essential feature of resilience is diversifying into new activities but little is known about whether major economic crises accelerate or decelerate regional diversification. This article shows how crises impact the development of new technological capabilities within U.S. metropolitan areas by examining three of the largest downturns in U.S. history, the Long Depression (1873-1879), the Great Depression (1929-1934) and the 1970s recession (1973-1975). We find that crises (i) reduce the pace of diversification in cities and (ii) narrow the scope of diversification to more closely related activities. This pattern seems general as it also holds for smaller, local crises. Evidence is presented that this general pattern of technological diversification strongly hampers employment growth. Additionally, we find that diverse cities generally diversify more strongly during times of crisis.