This assumption seems justified both on the basis of the literature and the findings in previous chapters, and is widely used in the literature (Shen and Whalley, 2013). In combination with labour force survey data (2001-15), national accounts data have been used to make empirical estimates of the extent to which labour and capital are substitutes in Thailand. The same is the case for high-skilled and low-skilled labour, where high-skilled labour has been defined based on major occupational groups (including groups 1-3: managers, professionals and associate professionals).