This paper develops a flexible recipe for identifying unobserved input allocations, as well as quantity- and revenue-based total factor productivity (TFP) across product lines, for multiproduct producers, using demand- and supply-side information. Applying variants of this recipe to a panel of plants manufacturing machinery in India from 2000–2007 yields sizable within-plant TFP differences. Removing an average plant’s lowest-performing product increases the unweighted average of plant-level revenue-based productivity by 10%–65%. A 1 standard deviation decline in product-level revenue-based TFP generates around a 6 percentage point increase in the probability of dropping that product.

We develop a decomposition of firm-level revenue-based TFP growth into six margins: i) mean quantity-based TFP growth, ii) mean growth in demand shifters, iii) intensive margin specialization effects, iv) scope effects, v) product adding effects, and vi) product dropping effects. We then estimate and decompose firm-level revenue-based TFP gains generated by increased Chinese import competition and input access using Indian manufacturing data. We find evidence of quality upgrading in response to increased output market competition, and that firms tend to add new products that are lower productivity than their incumbent goods in response to increased input access.