The Impact of Correction for Guessing Formula on MC and Yes/No Vocabulary Tests' Scores

Document Type: Research Paper


1 Islamic Azad University Tehran Central Branch

2 Islamic Azad University, Tabriz Branch


A standard correction for random guessing (cfg) formula on multiple-choice and Yes/Noexaminations was examined retrospectively in the scores of the intermediate female EFL learners in an English language school. The correctionwas a weighting formula for points awarded for correct answers,incorrect answers, and unanswered questions so that the expectedvalue of the increase in test score due to guessing was zero. The researcher compared uncorrected and corrected scores on examinationsusing multiple-choice and Yes/No formats. These short-answer formats eliminatedor at least greatly reduced the potential for guessing the correctanswer. The expectation for students to improve their grade by guessingon multiple-choice and Yes/No format examinations is well known. The researcher examined a method for correcting for random guessing (cfg) " no knowledge" on multiple- choice and Yes/No vocabulary examinations by comparing application and non-application of correction for guessing (cfg) formula on scores on these examinations. It was done to determine whether the test takers really knew the correct answer, or they had resorted to a kind of guessing. This study represented a unique opportunity to compare scores from multiple-choice and Yes/No examinations in a settingin which students were given the same number of questions ineach of the two format types testing their knowledge over thesame subject matter. The results of this study indicated that the significant differences were highlighted between the subjects' scores when cfg formula was applied and when it was not.


Bachman, L.F. & Palmer, A.S. (1996). Language testing in practice: Designing and developing useful language tests. London: Oxford University Press.

Budescu, D.V. (2008). A decision theoretical perspective on psychometrics: Analyzing Test-taking behavior. The internet., 21-23.

Cross, L.H., & Frary, R.B. (1977). An empirical test of Lord’s theoretical results regardingformula  scoring of multiple-choice tests. Journal of Educational Measurements 14, 313-321.

Cureton, E.E. (1966). The Correction For Guessing. The journal of Experimental Education. 34 (4). The Internet.,4.

Dennis, R.(2000). Let's talk about the "correction for guessing" formula. The Internet., 1-5.

Diamond, J., & Evans, W. (1973). The correction for guessing. Review of Educational Research 43, 181-191.

Frary, R. B. (1988). Formula scoring of multiple-choice tests (correction for guessing).No. 3 in the series; Instructional Topics in Educational Measurement, B. S. Plake, Editor. Educational Measurement: Issues and Practices, 7(2), 33-38.

Frary, R.B. (1982). A simulation study of reliability and validity of multiple-choice test scoresunder six response-scoring modes. Journal of Educational Statistics 7, 333-351.

Harvey, L.O. (2004). Detection sensitivity and response bias. The internet., 3.

Jones, A.C. (2006). Correcting for Guessing Increases Validity in Multiple-Choice Examinations in an Oral and Maxillofacial Pathology Course. The internet., 12-16.

Kasten, G. (1982). Correction for guessing. Evaluation Review.6 (6), 837-841. The  Internet. http://

 Kitao,K.&Kitao S.K.(1998). Test Design. Retrieved October 12, 2009: test/design.htm, 4-6.

Lord, F.M. (1975). Formula scoring and number-right scoring. Journal of Educational Measurement 12, 7-12.

Malcolm, J.S. (1968). The penalty for not guessing. Journal of Educational Measurement. (2). The Internet., 16-22.

Miller, E.T. (2009). Tactics and guessing. The internet. The official GMAT Blog.htm, 4-12.

Mousavi, S.A. (1999). A Dictionary of Language Testing. Tehran: Rahnama Publications, 68-70. 

Paul, J. (2007). Improving educational assessment by incorporating confidence measurement, analysis of self-awareness, and performance evaluation: The computer-based   alternative assessment (CBAA) project. The internet., 16-22.

Prihoda, T.J. & Pincjard, N. & McMahan, C.A. & Jones, A.C. (2006). Correction for guessing increases validity in multiple-choice examinations in an oral and maxillofacialpathology  course. Journal of Dental Education 70 (4), 378-386.

Rowley and Traub (1977). Formula scoring, number right scoring, and test-taking strategy. Journal of Educational Measurment 14 (1), 15 – 22.

Talento-Miller, E. (2009). Tactics & Guessing. The internet., 4-12.