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ERIC Number: EJ948623
Record Type: Journal
Publication Date: 2011-Jun
Pages: 11
Abstractor: ERIC
Reference Count: 23
ISSN: ISSN-0039-8322
Estimating Guessing Effects on the Vocabulary Levels Test for Differing Degrees of Word Knowledge
Stewart, Jeffrey; White, David A.
TESOL Quarterly: A Journal for Teachers of English to Speakers of Other Languages and of Standard English as a Second Dialect, v45 n2 p370-380 Jun 2011
Multiple-choice tests such as the Vocabulary Levels Test (VLT) are often viewed as a preferable estimator of vocabulary knowledge when compared to yes/no checklists, because self-reporting tests introduce the possibility of students overreporting or underreporting scores. However, multiple-choice tests have their own unique disadvantages. It has long been acknowledged that guessing on multiple-choice tests affects test reliability and inflates scores, and scoring formulas such as "cfg" have been proposed to adjust scores for guessing, under the assumption that the probability of a correct guess is consistent among test takers. The effects of estimation of guessing on tests such as the VLT are complicated by the fact that distractors are chosen from the same frequency level of words as the correct answer, and therefore from the tested domain. This introduces the possibility that increases in scores due to guessing could vary depending on the proportion of words in the tested domain known by the test taker. This study aims to determine the relationship between proportions of words known and score increases due to guessing. For this study, the precise relationship between the proportion of words a student knows and their expected score was determined using elementary probability theory. As proportions of known words rises, so does the probability of correctly guessing the diminishing numbers of remaining unknown words. This results in a fairly consistent score increase of approximately 16-17 points on a 99-item VLT test until over 60% of words are known, at which point the score increase due to guessing gradually begins to diminish. Implications for educators and researchers are presented. (Contains 4 figures and 2 tables.)
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Publication Type: Journal Articles; Reports - Research
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A