Fig. 1

Effectiveness of supervision strategies for professional health care providers in low- and middle-income countries, as assessed with outcomes expressed as percentages. N = number of study comparisons. Red indicates results from a single study, which should be interpreted with caution. The numbers next to each spoke are the median of median effect sizes, in percentage-points, and (in parentheses) the number of study comparisons. For each comparison, the arrow points toward the study group with greater effectiveness. For example, routine supervision was more effective than controls by a median of 10.7 percentage-points. ^aThese are non-supervision strategy components (e.g., training) that could vary among study comparisons, but are the same for any two arms of a given study comparison (e.g., routine supervision plus training versus training)