In the current study, differential item functioning (DIF) detection using real data was conducted with the application of "Mantel-Haenszel (MH)", "Simultaneous item bias test (SIBTEST)", "Lord's chi-square", and "Raju's area" methods, both when item purification was carried out and when item purification was…

As English is widely accepted as a lingua franca in today's world, the importance of the language has been acknowledged globally in the present case. To rank the countries in terms of their English language proficiency, the EF Proficiency Index is prepared each year. In this study, five countries having the highest scores according to the Index…