**7.1 Spread of the intervention**

The two case studies show that the most successful villages are those where high level of diffusion of innovation has taken place with at least 80% of the households being included within a CHC. Mberengwa District achieved blanket coverage and were able to show over 90% uptake across most indicators. In Rusizi, it was found that villages which had less than 100 households were able to achieve 80% CHC training across all households in the village but only after 3 years. This is a realistic target if sufficient personnel and transport are available to run the program to its best level. The *size of CHCs* seems less relevant than the importance of reaching *all households* in a village, within one or two CHCs. In small villages of under 100 households this can realistically be achieved in the first year, but larger villages need another year to achieve blanket coverage. Perhaps a standard target would be 70 households per year per CHC facilitator. This shows that *village size* should be considered when selecting intervention area so as not to over work each facilitator. A critical mass is likely to be more successful to prevent the spread of diseases such as cholera and diarrhea and malaria, and so this becomes the ultimate test of effectiveness.

## **7.2 Quality of the intervention**

The cost-effectiveness of a program depends not only on the Value for Money it can achieve (i.e. how *many* benefits it can deliver, and the *quality* of those benefits), but also on the way the program makes the most of scarce resources and takes advantage of *economies of scale*. The more CHCs that each officer can supervise the less the cost for personnel. We have seen that the size of a CHC can vary from 30 to 100 people. Although Mberengwa demonstrates that a greater number of smaller CHCs (with around 40–50 members) may be more manageable, this may not be the most cost-effective method, as the more people per CHC facilitator, the less the program will cost per beneficiary. Typically, an EHO should be able to monitor one or two CHCs per day, traveling constantly between villages. Therefore, the most cost-effective design is to have at least 100 CHCs in a program monitored by 10–20 EHOs, depending on the transport. Critically, each EHO should have a motorbike with a dedicated fuel allowance, supplied directly to the district.
