Reliability: An instrument or technique which is reliable gives the same result when applied repeatedly to the same subject. This does not mean that the result is necessarily correct, but simply that it is reproducible. For example a measure of user satisfaction would be said to be reliable if it reported the same level of satisfaction from a user who was repeatedly queried. This does not mean that the user has this degree of satisfaction but simply that he or she always reports the same results. Whether the results are "true" requires that the instrument also has validity.