Río, Fernando delRebelo, Francisco2026-01-092026-01-092026-02-01Río, F. D., & Rebelo, F. (2026). Normalizing VES production functions: extending the supply-side system approach. Economics Letters, 259, Article 112794. https://doi.org/10.1016/j.econlet.2025.1127940165-1765a22361a3-360b-468f-8587-9ad4fb57506chttp://hdl.handle.net/10400.14/56454This paper extends the Klump et al. (2007) normalization procedure to Variable Elasticity of Substitution (VES) production functions. Normalization addresses identification issues in VES model estimation, allowing joint estimation of substitution elasticities and factor-augmenting technical change, while offering a tractable extension of the normalized supply-side system that bridges the gap between CES and more flexible VES specifications.engCapital-labour elasticity of substitutionFactor-augmenting technical changeIdentificationNormalizationNormalized supply-side systemVariable elasticity of substitution (VES)research article10.1016/j.econlet.2025.112794105025006056001648920600001