Fig. 2

Comparison of observed tuberculosis notifications in high-risk zones to expected cases due to chance. Panel a orders the 33 zones the study area according to each zone’s facility-based phase tuberculosis (TB) notification rate (also provided in Table 1); the red line shows the cumulative proportion of TB cases notified who reside in “high-risk” zones (y-axis) according to the cumulative proportion of the population in the high-risk zone (x-axis). The shaded area corresponds to the 95% simulation interval (2.5th and 97.5th percentiles) from 1000 simulations that assume the observed population size in each zone and observed total number of TB notifications, but assign TB cases to zones under the assumption that spatial heterogeneity of TB notifications in the area is driven only by population size and random chance. The vertical line at 22% of the cumulative population represents the cutoff for “high-risk” zones used in our primary analysis and shows that 62% of facility-based cases resided in “high-risk” zones, significantly higher than the corresponding simulation interval of 40–59%. Panel b compares the same observed facility-based phase cases from Panel a (red line) with the cumulative proportion of TB cases identified through active case finding during the community-based validation phase (blue line), with the zones ordered according to TB notification rates during the facility-based phase. The vertical line in this panel shows that 42% of community-based phase cases resided in the “high-risk” zones (22% of the population) identified based on notifications during the facility-based phase