Many studies in regional development and economic geography are focused on factors that determine regional growth. In this paper a review of existing studies of regional growth is presented. The explanation power of the most recent studies is tested using the case of Michigan economy. In particular, the impact of high-tech industries, social attractiveness factors and regional economic development policies on the per capita income growth rate for Michigan counties is studied. Finally, the difference in effect of the policy and other factors in rural and metropolitan areas is assessed. The results of this work might be helpful in setting priorities using different development policy instruments.