Modelling repeated ordinal reports from multiple informants

Cross-informant associations tend to be low for reports of children’s behaviours at one point in time. The paper extends the literature on multiple informants using data from a well-known longitudinal study of Quebec, Canada, boys to show how to estimate associations between repeated teachers′ and self-reports of aggressive behaviour. These associations, for both level and change, are derived from multilevel models for repeated measures of variables best treated as ordered categories. The ordering is represented by sets of continuation ratios, change by linear and quadratic functions of age, and the multivariate models are estimated using penalized quasi-likelihood. The analyses also incorporate a risk variable: socio-economic status (SES). The correlations between estimates of the growth parameters for the two sets of reports tend to be rather small and smaller than the cross-informant associations for levels. SES is associated with levels of aggression, more so for teacher reports than for self-reports, but not with the decline in aggression with age.