standard neoclassical theory would suggest that the rapid increase in supply of more educated labour should have constrained real wages andor that diminishing returns to a factor that is human capital should have set in again resulting in a reduction in real wages for the more educated the second principal paradox in the labour markets of developed economies is that despite an increase in the demand for skills there has been a decline in the share of middle skill occupations in total employment and a rise in the share of lower skilled occupations goos and manning the latter include occupations such as cleaners drivers department store sales people fast food operatives and other personal service workers technological change causing growth of employment at the top and bottom of the labour market and decline in the middle is also a factor in growing income inequality in countries such as the us johnson the factor that is behind this increase is skilled biased technical change sbtc a pattern of technical change over several decades which has favoured the wage and employment prospects of relatively skilled workers while simultaneously damaging the wages and employment of the less skilled machin and van reenan