The prediction of TOEFL reading item difficulty: implications for construct validity

The purpose of this study is to predict the difficulty of a large sample ( n = 213) of TOEFL reading comprehension items. A related purpose was to examine whether text and text-by-item interaction variables play a significant role in predicting item difficulty. It was argued that evidence favouring the construct validity of multiple-choice reading test formats requires signincant contributions from these particular predictor variables. Details of item predictability and construct validity were explored by evaluating two hypoth eses : 1) that multiple-choice reading comprehension tests are sensitive to 12 categories of sentential and/or discourse variables found to influence compre hension processes in the experimental literature; and 2) that many of these categories of variables identified in the first hypothesis contribute significant independent variance in predicting item difficulty. For the first hypothesis, correlational analyses confirmed the importance of 11 out of the 12 categor ies, while stepwise regression analyses, accounting for up to 58% of the variance, provided some support for the second hypothesis. The pattern of predictors showed that text and text-by-item variables accounted for most of the variance, thereby providing evidence favouring the construct validity of the TOEFL reading items.