To use WCF as WCF Rest service you have to enable webHttpBindings. It support HTTP GET and POST verbs by [WebGet] and [WebInvoke] attributes respectively. To enable other HTTP verbs you have to do some configuration in IIS to accept request of that particular verb on .svc files.
Concurrent validity is a measure of how well a particular test correlates with a previously validated measure. It is commonly used in social science, psychology and education. Don't miss these related articles:
Construct validity. Construct validity is the degree to which a test measures what it claims, or purports, to be measuring.. In the classical model of test validity, construct validity is one of three main types of validity evidence, alongside content validity and criterion validity.