Fig. 3

Results of the difference-in-differences analyses. a How peak (September–February) malaria case incidence rates changed from 2016 to 2017 at the health facility level in districts where indoor residual spraying (IRS) was removed (dotted line border), districts where IRS was introduced (solid green border), and the remaining comparator districts where there was no IRS in either year. At each health facility, blue indicates a drop in malaria incidence and red indicates an increase, and the intensity of the colour represents the magnitude of the change. b The results of Student’s t-tests comparing the rates of changing incidence across the two IRS scenarios