The vast and ever increasing collection of information about consumers by search engines, advertisers, data brokers, web merchants, and myriad other online and offline companies raises many concerns. A website that stores (and reads) your emails, records every search you make, knows what addresses you look for on its maps, and holds your documents may know more about you than any other single institution, perhaps even including your family members.
Imagine if your email provider reads your email – or some other data accumulator reads your tweets or social network page – and tells the airlines that you are going to a family funeral across the country. Suddenly, you only find that airlines only offer you seats at a very high price. Think that you can hide your identity by searching before you sign in to buy? Doubtful. Web trackers likely know who you are using IP addresses, cookies, or other tricks invisible to most users.
One of the concerns about this data collection is differential or discriminatory pricing. Consumer advocates and others worry that merchants will use personal information to determine how much each individual consumer is willing to pay for something. That consumer then receives an individual price based on that consumer’s interest, need, income, buying patterns, and other factors. The next consumer pays a different price.
What’s the matter when a merchant charges one consumer a different price than another consumer? This is a surprisingly complicated question to answer.
Economists call the gap between what consumers are willing to pay and the market price the consumer surplus. If consumers lived in the economist’s hypothetical world of many buyers, many sellers, and a fair and transparent marketplace, consumers would expect to find prices based on marginal cost of production with lots of consumer surplus. Differential pricing is a merchant’s dream, with each customer paying a price based on willingness to pay rather than a standard price. Differential pricing could end the consumer surplus.
In the offline world, a merchant typically sets a single price for all consumers. The book is $12.99 to anyone who wants to buy it in the book store. Gasoline is $3.25 a gallon no matter how low a car’s gas tank is or how much the car cost.
In reality, things aren’t that simple in the offline world. The bookstore offers consumers a frequent shopper card (sometimes free. sometimes paid) with a discount on all purchases. The consumer with the card pays less than a consumer without one. The gas station offers a discount on Tuesdays because that’s a slow day. The movie theatre offers lower prices early in the day and higher prices in prime time. Many sellers offer a discount to seniors.