The reasons for equating of test are different from one situation to another, but in general they can be classified
in three categories: one important and fundamental reason for equating can be improving the cohesion and integrity
of grades of test in order to not being forced to testine several times. To assure one of justice and equity of a test, or
to neutralize the effect of exercise, in the process of setting the test several forms are often needed. For measuring
the learning merit of children, for example, dual forms were set and published in a learning merit test