licensing is associated with about 14 percent higher wages, but the effect of governmental certification on pay is much smaller … positively associated with wages. We find little association between licensing and the variance of wages, in contrast to unions …

licensing is associated with about 18 percent higher wages, but the effect of governmental certification on pay is much smaller … little association between licensing and the variance of wages, in contrast to unions. Overall, our results show that …

licensing is associated with about 14 percent higher wages, but the effect of governmental certification on pay is much smaller … positively associated with wages. We find little association between licensing and the variance of wages, in contrast to unions …