Robust correlates of county-level growth in the United States

Higgins <italic>et al</italic>. (2006), report several statistically significant partial correlates with US per capita income growth. However, Levine and Renelt (1992) demonstrate that such correlations are hardly ever robust to changing the combination of conditioning variables included. We ask, whether the same is true for the variables identified as important by Higgins <italic>et al</italic>. Using the extreme bounds analysis of Levine and Renelt, we find that the majority of the partial correlations can be accepted as robust. The variables associated with those partial correlations stand solidly as variables of interest for future studies of US growth.