A cost-benefit analysis based on visual-performance models is derived by consideringsthe current consensus lighting recommendations, RQQ #6, as implicit estimates ofscost-effective lighting. There is only partial consistency between models and thesesrecommendations. The consistency analysis provides a quantitative basis for thesesrecommendations, delineates their limits of applicability, and suggests changes insthem for handling low reflectance tasks, aged workers, high electrical costs, orsconditions where high visual speed and accuracy are very valuable.