This study has developed and tested an approach and a methodology for identifying persuasive communication appeals that have the best chances of influencing people's attitudes and behaviour in the area of social marketing, specifically, family planning. It can be used by social marketers for designing communication campaigns. Social psychologists and sociologists have emphasized that people's value systems and their perceptions of how these values are related to an object (behaviour or person), have an important influence on their attitudes and behavior towards that object. In designing a family planning communication, the choice of its two most important elements-'message appeal' and 'source'-requires an understanding of the value system and perceived value-instrumentalities of the target population. Research in family planning has neglected the problem of 'appeal' determination. A methodology for generating relevant information about the target population, for the purpose of designing communications, should elicit their value systems, and perceived value-instrumentalities, in addition to measures of communication effects, media demographic and socio-economic variables. The instruments used for ascertaining values should allow for unconstrained, 'value-free' responses. The methodology should have cross-cultural applicability, and should allow for the use of standard sampling procedures. The methods used in commercial advertising field involve preselection of dimensions and/or objects on which responses are sought, thus, restricting observation to target population's views about our concerns rather than their concerns and values. The methodology tested in this study uses a relatively new method, called ECHO technique, for generating value hierarchies of target populations as well as perceived patterns of influences operating on their lives. The method combines the advantages of a survey method with those of a phenomenological approach. It preselects valence-good or bad-but allows for the dimensions or objects to be empirically generated. The value responses as well as sources of influence are classified into categories by indigenous classifiers. A measure of value-instrumentality that uses the values generated in the same interview has been developed and tested in this study. The fieldwork for the test was conducted in North India. The results confirm the postulated relationships among subsets of values and the criteria variables-practice, attitude, intention and awareness concerning family planning. Similarly, strong and consistent relationships emerge between criteria variables and value-instrumentalities of family size and family planning. Among the more important values of the sample concern: health, children's welfare and children turning out to be 'worthy', family harmony, community disputes and occupation. The users of family planning have a more positive outlook and perceive a greater control over events in their lives than do non-users. The values provide content for messages. A framework for developing communication strategies that segments target population on the basis of: usage, intention, and attitude, is used in the study. Among current users and those who intend to use family planning in future, favorable value-instrumentalities should be emphasized in communications, particularly those between family planning and good health, family harmony, children's welfare and chances of their turning out to be used with nonusers who do not intend to practice in the future, however, favorable instrumentalities will have to be promoted as such perceptions are not widespread, and are sometimes unfavorable. Communications designed to counter widespread beliefs about anti-God nature and adverse effects of birth control methods, particularly sterilization, are needed. Communications promoting appreciation of reduced infant-and child-mortality and negative economic value of having many children are also recommended. The results indicate that influential people of a community with whom the audience can identify, and religious leaders and holy men are more likely to be effective 'sources' of communication than urbanized change agents. Use of local dais-midwives-is recommended for promoting family planning acceptance. A product-mix that allows for more alternative methods --including the pill-is also recommended in view of the widespread anti-God and negative-health connotations of sterilization.