intensive presence of activities prior to the NCDDP - and it is likely that successes reported there cannot be used as a basis for national generalization. Bearing these caveats in mind, a closer look at the evidence presented in Table 2 is carnied out below. The quality of information is not investigated here and all surveys are assumed to be of reasonable quality.

All evidence on ORT utilization before NCDDP is derived from the two control trials in small areas. It seems reasonable to assume that the data related to ORS practice would hold nationally. However, the percentage of ORT use prior to NCDDP may be inflated by the fact that the first round of the Dakahlia 1980 control trial started a few months after the ORT promotion activities. The data on continuation of feeding during episodes could have benefitted from other supportive evidence, but the case made for weak management of episodes seems reasonable. For the period after the initiation of the NCDDP, the percentage of ever use of ORS differs between the National (66%) and the Menoufla (80%) surveys, despite the fact that both surveys collected information concerning children less than 2 years of age. The difference in utilization may be attributed to the concentration of efforts in Menoufia that started before NCDDP. The evidence suggests that two out of three mothers (with young children) have at least once used ORS and that most women (over 85% of respondents) can mix it properly. The proper mixing was actually observed by interviewer.

To sum up, most available studies and reviews are in agreement that the NCDDP has succeeded in improving knowledge and general use of oral rehydration salts. The percentage of ORS use in recent episodes and the quality of such use are two key pieces of information for inferences about impact.

# a) _ORS Use in Recent Eisoes_

It is surprising to note that data on ORS use have not been presented on a national basis to support causality inference. A probable explanation is the fact that the reference periods of the last episodes in the national KAP studies (prior to 1988) were almost open ended. The question referred to the experience of diarrhea since the previous Ramadan (the month of fasting in Egypt which occurred several months before the survey). For each child experiencing diarrhea in the reference period, questions were asked about use of ORS in the most recent episode. The rate obtained from the 1988 national KAP for this rather long reference period is 51 %, which is almost identical to the Menoufla rate of 52% (the Menoufia study suffers from the same problem of long reference period). It is strongly suspected that this methodology tends to overstate percentage utilization. The Dakahlia evidence refers to children under the age of five and the recall period was 2 weeks prior to the survey. The level of utilization reported (81 %) is impressive and deserves a closer look to determine its validity for national inference.

In a critical assessment of the utilization of ORS use rates as an ORT program indicator, Larson and Mitra (1990) _19_ refer to 4 national surveys taken in Bangladesh during the 1980's that gave use rates ranging from 14 to 80 percent. The authors discuss three methodological issues to which use rates are sensitive: "The terms used to describe a diarrheal episode, the reference period of the episode for which treatment information is collected and the prompting sequence 10