“…Budd, Chi, Wang, and Xie (2014) and Besley and Burgess (2002) confirm that union density does not affect the average wage level, but is positively associated with aggregate productivity and output. The divergence between wages and productivity has also been discussed in terms of the impact of heavy and autonomous capitalisation on rising productivity (Nwaokoro, 2006), differences in the wage-setting processes in different countries (Millea, 2002), which is closely connected both with the labour market and the consumer goods market (Nikulin, 2015), market frictions, such as search costs (Zoega & Booth, 2005), economic growth, education and skill-level differences (Semeels, 2005) and other social norms (Frazis & Loewenstein, 2006), lags in adjustment and imperfect competition in the product and labour market (Sharpe et al, 2008), degree of unionisation and firm’s size (Organization for Economic Cooperation and Development [OECD], 2001) and labour market policies.…”