Assessing Affix Knowledge Using Both Pseudoword and Real-Word Measures

Purpose: Growth in morphological skills has been documented during mid-elementary grades, but little research has examined knowledge of affix morphemes separate from whole words. This study evaluated affix knowledge using a combination of real-word and pseudoword tasks. Methods: Forty-five third-grade and 32 fifth-grade students participated. Students were assessed on word identification, vocabulary knowledge, and affix proficiency. Sixteen prefixes and 16 suffixes were studied using real-word and pseudoword stimuli. Results: Analyses indicated variability in which affixes were known. Vocabulary and word-reading abilities accounted for substantial variance in affix knowledge. On almost half of the pairs of real-word and pseudoword items, students' performed significantly differently, accurately responding on only one. Conclusions: Performance on the 2 types of morphology tasks (real-word and pseudoword) varied for a noteworthy portion of the affixes studied. These results indicate that using both types of measures may be important for investigations of morpheme knowledge.