Table 1

Parameter estimates for models 1–4

Independent variable(1) OLS(2) OLS(3) OLS(4a) 2SLS(4b) OLS
% union−0.028* (0.01)−0.028** (0.01)−0.027** (0.01)−0.049**(0.01)
Policy liberalism−0.019 (0.06)−0.049 (0.06)−0.036 (0.05)−0.049 (0.70)
% trade, transport, utilities−0.035 (0.02)−0.028 (0.02)−0.041 (0.03)
% mining, logging, construction0.054*** (0.01)0.053*** (0.01)0.053*** (0.01)
% manufacturing−0.002 (0.01)0.001 (0.01)−0.006 (0.01)
Right to work0.142* (0.06)
State fixed effects
Year fixed effects
Population weights
Observations12501250125012501250
Root mean square error0.14240.14240.13890.13710.1422
  • Cluster-robust SEs in parentheses.

  • *p < 0.05, **p < 0.01, ***p < 0.001.

  • 2SLS, Two-Stage Least Squares; OLS, Ordinary Least Squares.