Single-product versus uniform SSNIPs

It is common to apply a SSNIP test with a uniform price increase on all products in the candidate market. We show that in situations with asymmetries - for example variations in revenues - a uniform SSNIP test may suggest that the relevant market should include more products even though it could be profitable to increase the price of only one product in the candidate market. Our results are illustrated with some findings from a survey in a local grocery market.