More generally, they keep prices artificially high and therefore depress average real wages for the economy as a whole. By restricting output, they tend to reduce employment levels in the affected sectors, except when a protected environment allows over-staffing to be maintained, and labour demand may be further reduced if wages in these sectors contain an element of product-market rents. Combining PMR indicators with measures of labour market regulations, Boeri et al. ( Using time-varying indicators of PMR, Nicoletti and Scarpetta (2004) find that product market reforms contribute to increasing non-agricultural employment rates.