Since 1970s item response theory became the dominant area for study by measurement specialist in education industry.
The common models and procedures for constructing test and interpreting test scores served the measurement specialist and other test users well for a long time. In this paper, a number of assumptions about the
classical test theory are discussed. In addition, the contemporary test theory that is item response theory (IRT) will be discussed in general. There are four strong assumptions about the
probability theory of item response theory such as the dimensionality of the latent space, local independence theory, the item characteristics curves and the speediness of the test. Furthermore, this discussion aimed to assist departments of education in considering the IRT that contributed in introducing the use of computerized adaptive testing (CAT) as they move to transition testing program to online in the future.