The aim of this study is to introduce the concept of equating, its implications and methods in the domain of measurement and
evaluation. In this paper the two kinds of classic equating and item response theory (IRT), through collecting data and analyzing
them were investigated along with considering advantages and disadvantages of these methods. According to these different
cases errors of equating were reckoned through computer software’s BILOG and SPSS. Considering a series of available data
and methods of measurement, and using equating, the test were completely explained through the data drawn from two tests.
Consequently, the two tests were equated with the same scale, and accuracy of equating was estimated. Finally, the advantages
and potential applications of equating of tests were considered in classic theory and item response theory. This study has
implications for educational measurement and testing procedures especially for adaptive testing and test constructing.