This study examined the impact of instructor use of hesitation forms ("uh," "ah," "um," and "well") in an initial encounter with the students on three measures of teaching effectiveness: students ratings of teacher quality, student recommendations to hire, and lecture listening. The instruction of any amount of hesitant speech significantly lowered instructor effectiveness as measured by each dependent variable. Generally, the use of higher frequencies of hesitation forms was more damaging than the use of lower frequencies. The findings of this study suggest that the use of other forms of powerless language may also detract from the teacher effectiveness.
Johnson, Craig E.; Vinson, Larry; Hackman, Michael; and Hardin, Tom, "The Effects of an Instructor's Use of Hesitation Forms on Student Ratings of Quality, Recommendations to Hire, and Lecture Listening" (1989). Faculty Publications - College of Business. 55.