| Abstract: | Examinees who take credentialing tests and other types of high-stakes assessments are usually provided an opportunity to repeat the test if they are unsuccessful on initial attempts. To prevent examinees from obtaining unfair score increases by memorizing the content of specific test items, testing agencies usually assign an alternate form to repeat examinees. Given that the use of multiple forms presents both practical and psychometric challenges, it is important to determine if unwarranted score gains occur. Most research indicates that repeat examinees realize score gains when taking the same form twice; however, the research is far from conclusive, particularly within the context of credentialing. For the present investigations, two samples of repeat examinees were randomly assigned to receive either the same test form or a different, but parallel, form on the second occasion. Study 1 found score gains of about 0.79 SD units for 71 examinees who repeated a certification examination in computed tomography. Study 2 found gains of 0.48 SD units for 765 examinees who repeated a radiography certification examination. In both studies score gains for examinees receiving the parallel test were nearly indistinguishable from score gains for those who received the same test. Factors are identified that may influence the generalizability of these findings to other assessment contexts. |
