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ASPECTS OF PRECIPITATION ENHANCEMENT 39 lanches are predicted. Compensatory mechanisms for clear liabilities have appeared to be more important in winter than in summer projects. Observation (Figure 2.6) of the project's effects is the third key factor. The effects of seeding will be observed by community members with interest, and they will come to conclusions about what cloud seeding is doing to their weather. If sound evaluation data are brought for- ward by scientists, this will carry some weight. However, the effects that the people themselves experience will be decisive. These obser- vations are tied to belief in efficacy. If community members attribute [perceived or actual] positive effects-more rainfall and less hail for agriculture and more snow for ski areas-to cloud seeding, then project continuance is more likely to occur (Farhar and Fitzpatrick 1990). This indicates that it would be wise for those introducing the cloud seeding technology (the broker/change agent in Figure 2.6) to provide community representatives with observational experiences by means of available observing or numerical modeling technology, and laboratory or limited-scale field demonstrations. The other factors (Figure 2.6) that influence community response and consequent decisions are obviously important. For those who will listen, scientific answers about the efficacy of cloud seeding do exist, but science is ever-advancing and "final and complete" conclusions are elusive. This aspect often confounds the public, as noted earlier. What would be ac- ceptable as proof of increased water? It is important to have a practical answer to this question. To speculate statistical terms, for example, scien- tists may require broadly based evidence of a measurable effect at the 99% significance level, whereas the user or the public may be satisfied with significance at the 80% level. The perception of drought conditions as a predominant decision-in- fluencing factor has stirred some scientific concern. Opponents have often cited cloud seeding as a cause of drought. Also, interest increases when cloud seeding is perceived as an effective drought-relief technol- ogy; this is not a surprising finding of the CSU study. However, scien- tists generally agree that the most soundly based approach to stabilizing water supplies is to conduct sustained rather than crisis-reactive cloud seeding projects. Drought is normally caused by abnormally persistent flow patterns in the global scale atmospheric circulation; this in itself means to scientists that cloud seeding is not a cause of drought. Drought conditions commonly (but not always) offer few suitable clouds; seed- ing in such conditions can be counter to the scientific basis. One cannot expect to make scientists of the populace in a public meeting or two. However, only efforts to educate those concerned can establish a soundly based belief in efficacy and cowlter the all-too accurate cli- che that "interest in cloud seeding is soluble in water" (Farhar and Fitzpatrick 1990).