Being able to clearly present information in a way that students understand is an important teaching skill, and has been shown to positively related to student outcomes. It includes behaviors such as putting an outline on the board, using concrete examples, giving multiple examples, repeating difficult ideas, pointing out practical applications, and stressing important points.
In a study by Rodger, Murray, & Cummings (2007) it was tested whether teacher clarity and student's text anxiety interact in how they affect student outcomes. While teacher clarity has been shown to be positively related to outcomes, text anxiety tends to have a negative effect. Students completed measures of intelligence and test anxiety and were randomly assigned to high teacher clarity or low teacher clarity conditions, defined by the presence or absence of specific teaching behaviours in a videotaped lecture with content held constant across conditions. Measures of motivation and self-efficacy for learning the material were completed immediately post-treatment, then one week later participants completed an achievement test based on the material contained in the lecture and assigned homework. Results revealed significant beneficial main effects for high vs. low teacher clarity for both achievement and motivation measures, but no aptitude–treatment interaction between teacher clarity and student test anxiety. This study shows that while both teacher clarity and test anxiety affect the learning process, they do not specifically interact in any special way.
Source:
Rodger, S., Murray, H. G., & Cummings, A. L. (2007). Effects of teacher clarity and student anxiety on student outcomes. Teaching in Higher Education, 12(1), 91-104.