| Abstract: | Equating of tests composed of both discrete and passage-based multiple choice items using the nonequivalent groups with anchor test design is popular in practice. In this study, we compared the effect of discrete and passage-based anchor items on observed score equating via simulation. Results suggested that an anchor with a larger proportion of passage-based items, more items in each passage, and/or a larger degree of local dependence among items within one passage produces larger equating errors, especially when the groups taking the new form and the reference form differ in ability. Our findings challenge the common belief that an anchor should be a miniature version of the tests to be equated. Suggestions to practitioners regarding anchor design are also given. |
