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α: calibrated so average coauthorship-adjusted count equals average raw count
In response to a price change by a single seller, it is common for the density of sellers in the market to influence both the quantity response of consumers and the price response of other sellers. Using field experiment data collected around a series of exogenously imposed price changes we find that an individual retailer with a larger number of competitors faces a more-responsive demand. This finding is fundamental to a predicted inverse relationship between market prices and the number of competitors. We also examine the reaction of rival stations to exogenous price changes, and find that the magnitude of a competitor's response is inversely related to the density of stations in the market.