On healthcare as a imperfect market

Healthcare is an imperfect market in healthcare it is difficult to compare sellers such as Doctors quality and prices and the buyers requirements in other words there is asymmetric information flow as according to the text. In healthcare the seller (doctors) control all the information about health care and the consumer (patients) tend to avoid medical services until they need them. Even if payer (insurers) or consumers try hard to compare sellers (doctors) and their products, data are expensive to collect and complex to interpret. Doctors can set up monopolies or oligopolies in which neither purchasers nor consumers can shop or even easily negotiate services or prices.