Fig. 4

Tornado graph of sensitivity analysis for mean cost per person for house improvement alone arm. The simulated effect of changes in staff costs and population covered on estimated mean cost per person. The left panel shows the change in cost per person from the baseline, i.e. trial mean estimate, when staff costs and population covered are varied. The lighter (dotted) shade of the bar corresponds to increasing input values. The darker (solid fill) shade corresponds to decreasing input values. For both LSM and HI + LSM, the cost per person increases with increasing staff costs; and reduces with increasing population covered; and vice versa. The right panels show the corresponding frequency distribution of simulated estimates of cost per person. The area bound by the black vertical line represents the upper limits of the 5th and 95th percentiles (i.e. 90% uncertainty interval) of simulated cost per person estimates of HI: US$19.99–29.52. The minimum, most likely and maximum values, respectively, used for the distributions were: Staff cost: $ 43,798; $ 120,616; $ 120,616. Population covered: 3654; 4568; 5482