furthermore large income disparities can hold back economic growth by weakening aggregate demand united nations the widening of income gaps between employees with differing education levels in the s and s was something of a surprise considering the expected labour supply and demand trends on the one hand the expansion of education systems increased the supply of better qualified personnel on the other it was expected that liberalizing economic reforms would benefit the sectors that mainly used more plentiful factors of production especially low and mediumskilled labour the outcome of these processes would have been to boost the wages of the low and mediumskilled workers of the multiple factors that could have contributed to this trend it was not possible to identify any single key cause it being considered that a series of interactions are likely to be responsible fishlow and parker