Secret Shopping is a tool used by market research companies to measure quality of retail service or gather specific information about products and services. Secret shoppers posing as normal customers perform specific tasks—such as purchasing a product, asking questions, registering complaints or behaving in a certain way – and then provide detailed reports or feedback about their experiences.

Secret shopping began in the 1940s as a way to measure employee integrity. Tools used for mystery shopping assessments range from simple questionnaires to complete audio and video recordings. Many secret shopping companies are completely administered through the Internet, allowing potential secret shoppers to use the Internet to register for participation, find secret shopping jobs and receive payment.
The most common venues where secret shopping is used are retail stores, movie theaters, restaurants, fast food chains, banks, gas stations, car dealerships, apartments and health clubs, as well as health care facilities. In the UK, secret shopping is increasingly used to provide feedback on customer services provided by local authorities and other non-profit organizations, such as housing associations and churches.