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.