Deriving passage difficulties for a tracking study via the Cloze technique

The current report demonstrates the importance of formally accounting for passage difficulty when using the tracking procedure. Cloze responses to 82 encyclopedia excerpts (343-349 words each) were obtained from a large pool of normal-hearing adults and scored verbatim. Passage difficulty, derived via ANOVA, was then defined as the deviation of a passage's mean Cloze score from the score for all passages, corrected for differences among respondents. The passage difficulties were applied in an alternating conditions tracking experiment with one adult cochlear implant user. Conditions included conventional auditory-visual and auditory-only tracking and experimental mode-switching techniques in which the talker changed modalities during the correction phase. An ANCOVA of the word-per-minute scores was conducted, with passage difficulty as a covariate and passage adjustment values as the output. Tracking rates and percentage of words correct from the beginning and end of training were examined. Use of adjusted data reversed the interpretation of performance change, demonstrating the need for determining passage difficulties a priori.