Instructional coaching has improved student outcomes in the United States, and may help to solve
Kenya's literacy problems. Coaching is costly, however, and evidence is lacking regarding the most costefficient
teacher-to-coach ratio. We used student literacy outcome data from more than 8000 students
participating in the Kenya Primary Math and Reading Initiativeda randomized controlled trial of
instructional interventions in public and nonformal schoolsdto fill this gap. Coaches in larger public
zones made fewer visits per teacher, and teacher-coach ratio and student performance were negatively
associated. Using causal methods, we concluded that lower ratios might improve nonformal school
outcomes.