Services marketers have argued that risk perception is higher for services because they lack the search attributes of products (i.e. tangible properties that can be inspected prior to consumption). In terms of risk perception, marketers and economists identify three broad classes of purchase; search goods, experience goods and credence goods with implications for consumer evaluation processes. Search goods, which include most tangible products, possess tangible characteristics that allow consumers to evaluate quality prior to purchase and consumption. Experience goods, such as restaurants and clubs, can only be evaluated with certainty after purchase or consumption. In the case of credence goods, such as many professional services, the consumer finds it difficult to fully appreciate the quality of the goods even after purchase and consumption has occurred. Difficulties evaluating quality after consumption may arise because the cost of obtaining information is prohibitive, or because the consumer lacks the requisite skills and knowledge to undertake such evaluations. These goods are called credence products because the consumer's quality evaluations depend entirely on the trust given to the product manufacturer or service provider.