Measuring morphological awareness in English-speaking adults: How task format, item features, and reading comprehension affect test item difficulty

This study investigated how task format, reading comprehension ability, and linguistic item features influence item difficulty in morphological awareness (MA) assessments among adult English speakers. In our pre-registered study, we analysed response accuracy from 102 participants (L1 and L2) who completed four pseudoword-based MA task types—short text, single sentence, picture, and word analogy—alongside a standardised reading comprehension test. Reading comprehension significantly predicted item accuracy, suggesting that individual differences in comprehension ability systematically affect item difficulty. Task type also significantly affected difficulty, with word-analogy items being the easiest. The other three types showed comparable difficulty. The presence of orthographic shifts did not significantly influence item difficulty. In contrast, morpheme type had a strong effect, with inflection items being easier than derivational ones. Among cue-related item features, the types of pseudowords and the presence of spelling cues in items significantly affected item difficulty. Our study calls for attention to task design and linguistic item features that can improve the psychometric qualities of MA assessments by ensuring items align with the intended purpose—whether to profile morphological skills or differentiate individual differences.