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.
