The value of the elasticity of substitution between labor and capital (ó) is a "crucial" assumption in the study of factor incomes (e.g., Piketty (2014a), Piketty and Zucman (forthcoming), Karabarbounis and Neiman (2014)) and long-run growth (Solow, 1956). This paper begins by examining the...

Nearly 75 years ago, John Hicks introduced and formalized the concept of the elasticity of substitution between capital and labour and its relation to derived demand. The resulting formula has proven very useful in understanding the derived demand for productive factors, the distribution of...