Guttman scale analysis of dental health attitudes and knowledge

Indexes on attitudes and knowledge are very often used in community dentistry research. However, such indexes are seldom evaluated with respect to validity. In the social sciences, complicated and advanced scaling methods are widely used. One of the methods, The Guttman scaling, is a means of analyzing the underlying characteristics of several items in order to determine whether the scale is unidimensional and cumulative. The purpose of the present study was to develop and evaluate two Guttman scales: 1) attitudes to prevention of dental diseases and 2) knowledge about sugar and caries. The scales were evaluated on the basis of survey data on health behavior, dental attitudes and knowledge among parents of Danish children 6 years of age. A total of 193 parents (71% of original sample) responded to a postal questionnaire including questions on attitudes to prevention of dental diseases and knowledge about sugar and caries. In the analyses, the scales were evaluated according to standard criteria of scalability: Coefficient of Reproducibility, Minimal Marginal Reproducibility, and Coefficient of Scalability. The analyses showed that unidimensional and cumulative scale was indicated for attitudes to prevention while the scale on knowledge about sugar and caries failed on the criteria of validity. In community dentistry, future studies ought to be more concerned with the construction and testing of scaling models in order to provide valid analyses of dental health attitudes and knowledge.