Results of the study could be affected by research instruments not been standardised for different ethnic or cultural examinees. The issue of standardization of the research instruments in terms of ethnic or cultural differences of the examinees could also affect the assessment of the comparability between CTT and IRT test item parameters estimates is the validity and reliability. According to Tilov, et al (2012), ‘standardized research instruments facilitate data collection and monitoring, yet standardization requires that researchinstruments be adapted for use in different cultures because of the increase in diversity in research that examines practices across different cultures