ISSN 1842-4562
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Validity, Reliability and Difficulty Indices for Instructor-Built Exam Questions

Gholamreza JANDAGHI


instructor-built exam, content validity, face validity, reliability, coefficient of discrimination, coefficient of difficulty


The purpose of the research is to determine college Instructor’s skill rate in designing exam questions in chemistry subject. The statistical population was all of chemistry exam scripts for two semesters in one academic year from which a sample of 364 exam scripts was drawn using multistage cluster sampling. Two experts assessed the scripts and by using appropriate indices and z-test and chi-squared test the analysis of the data was done. We found that the designed exams have suitable coefficients of validity and reliability. The level of difficulty of exams was high. No significant relationship was found between male and female instructors in terms of the coefficient of validity and reliability but a significant difference between the difficulty level in male and female instructors was found(P<.001). It means that female instructors had designed more difficult questions. We did not find any significant relationship between the instructors’ gender and the coefficient of discrimination of the exams.