Production functions provide a mapping from the firms' input quantity and productivity to output quantity. This mapping only generates unbiased estimates if input and output quality variation within and between observation units is accounted for. I review and classify state-of-the-art methods to...

We develop a model of vertical innovation in which firms incur a market entry cost and choose a unique level of quality. Once established, firms compete for market shares, selling to consumers with heterogeneous tastes for quality. The equilibrium of the pricing game exists and is unique within...