This paper uses detailed weekly data on sales of hardcover fiction books to evaluate the impact of the New York Times bestseller list on sales and product variety. In order to circumvent the obvious problem of simultaneity of sales and bestseller status, the analysis exploits time lags and...

Innovations in information technology have increased the prevalence of markets with large numbers of products. Each week, for example, an average of over 800 books are published, and an average of over 1,100 iOS apps are released in Apple's App Store. This review summarizes existing research...

We examine merging firms' additions and removals of products for a sample of 66 mergers across a wide variety of consumer packaged goods markets. We find that mergers lead to a net reduction in the number of products offered by merging firms. Merging firms tend to both drop and add products at...