Classical Test Theory.

Classical test theory (CTT) is a branch of psychometrics that aims to predict the outcome of entire tests or the responses of specific test items based on completed tests and test items used for data collection. While CTT still has support in the psychometric community, it is generally used today for the purpose of testing reliability, along with other theories of assessment, in various assessment instruments. It is one of the most influential theories regarding test scores in the social science field.