In other words, the presence of increasing returns to scale, along with forward and backward linkages, allow firms to purchase intermediate inputs at lower costs. Several firms specialise in producing complementary products, reducing overall production costs. This refers to the idea that an industry gains from having a constant market for skills. If there are market shocks, firms can adjust to changes in demand if they have access to a deep and broad labour market that allows them to expand or contract their demand for labour.