The African Statistical Journal, Volume 10

Abstract

Responses in participatory on-farm trials are often measured as ratings (scores on an ordered but arbitrary scale) or rankings (respondents are simply asked to order treatments). Usual analyses of variance and linear model-based analyses are not appropriate for these data. Alternatives, based on generalized linear models, are described. These methods can be successfully used when the designs are irregular, as typically occurs in participatory trials, and when covariates are measured on each plot or farm in order to identify GxE interaction.