page 16 the project documents reviewed" (American Public Health Association, 1982, p. 81). One of these was for a project without VHWs. Two of the<sup>other four cited</sup> evidence of positive impacts of VH W activities on health status and the other two demonstrated no rignificant effect. Although "nearly all the projects plan to evaluate outcome by measuring changes in health status, . . . many evaluation components are initiated but never completed ; others are executed late; and s1l others are never initiated" (ibid., pp. 79, 80).

As a result of this lack of information on the effectiveness of VHW activity, any estimate of a, the number of life-days-saved per VHW encounter, must be proposed even more tentatively than the estimates of b, above. However, by using expert judgements of VH W effectiveness, two independent estimates of a are possible, one from Ghanaian and the other<sup>from Javanese</sup> data and assumptions. Table 3 develops estimates of the number of life-days saved per VH W encounter based on primarily Ghanaian rough estimates of the effectiveness of the Ghanaian VH W at treating 13 different disease categories. Column (6) gives an estimate of the number of "needed" encounters witi a VHW per yt. , assuming that all of this need generates effective dem.. d by villagers for treatment outside the home and that no traditional healers, pharmacists or other providers substitute for the VH W. Based on this undoubtedly .high estimate of encounters per year, column (7) computes the average number of LDS per encounter to be 14.9.

The extent to which demand for the services of a VHW will fall short<sup>of</sup> "need" is difficult to estimate until a study such as those of Heller (1982)<sup>and</sup> M wabu (1983) on Kenya is available for VHWs in a country similar<sup>to that under</sup> consideration. Column (8) of Table (3) gives a rough estimate of such<sup>demand</sup> based on the assumption that the villagers will not accept any preventive or screening services from the VHW and that they do not<sup>demand "enough" care</sup> from the VHW for colds, diarrhea, schistosomiasis and childhood pneumonia, because they seek other sources of care or because tney consider these symptoms to be insufficiently serious to warrant treatment. (It has been reported that blood in ttie urine, a symptom of schistosomiasis, is considered to be a mark of manhood in some cultures.) These assumptions<sup>reduce by half</sup> the total number of encounters by the VHW, but reduce the<sup>number of LDS by</sup> three-quarters so that the average LDS per encounter also drops by half to about 7.5, sdil a substantial number even under these admittedly pessimistic assumptions.

While the Ghanaian analysts computed total life-days lost under the current health system Cor 48 diseases and the impact that VHWs could be hoped to have on nine of those, the Michigan study considered<sup>each of only 31</sup> diseases at a much more disaggregated leveL Working from estimates of the incidence of each of these 31 diseases for each of six age-sex categories under each of eight different combinations of immunization, sanitation and nutrition programs, the Michigan study developed estimates of the impact of the VH Ws and of five other treatment combinations on mortality and morbidity in the rural Javanese population of 50,000.

Table 4 extracts from this work the information necessary to estimate the number of LDS per VHtW encounter in Java. Converting the<sup>estimated</sup> number of life-years saved from column (8) to days and adding the number of disability days from column (9) gives a total savings of 3,531,200 LDS. Dividing this total by the estimated number of encounters of 235,000 gives an estimated number of LDS per encounter of 15.0.