This study investigated the utility of all of the above (AOTA) as a test option in multiple-choice items. It aimed at estimating item fit, item difficulty, item discrimination, and guess factor of such a choice. Five reading passages of the Key English Test (KET, 2010) were adapted. The test was reconstructed in 2 parallel forms: Test 1 did not include the abovementioned alternative, whereas Te...

Matrix Factorization (MF) is one of the most successful Collaborative Filtering (CF) techniques used in recommender systems due to its effectiveness and ability deal with very large user-item rating matrix. However, when matrix sparseness increases performance deteriorates. Expanding MF include side-information users items has been shown by many researchers both improve general recommendation h...