A REGRESSION METHOD FOR ANALYZING ORDINAL DATA FROM INTERVENTION TRIALS

We consider the case of a community intervention trial evaluated with a series of cross-sectional surveys and having outcomes measured on an ordinal scale. We propose a modelling procedure that combines ridit a nalysis and linear regression methods. We use the multinomial distribu tion as the basis for variance estimation of the mean ridits and then use simple regression models to estimate differences (for example, bet ween intervention and comparison areas) among the ridits. We illustrat e this procedure with data from a community intervention trial promoti ng condom use, with the adoption of consistent condom use measured on a 5-point ordinal scale.