A Cautionary Note on IRT‐Based Linking of Tests With Polytomous Items

Published discussions of the year-to-year linking of tests comprised of polytomous items appear to suggest that the linking logic traditionally used for multiple-choice items is also appropriate for polytomous items. It is argued and illustrated that a modification of the traditional linking is necessary when tests consist of constructed-response items judged by raters and there is a possibility of year-to-year variation in the rating discrimination and severity.