Dear list members, I am facing a 3-level model, for which my research hypotheses suggest that the variance of both level-1 and level-2 residuals may be a function of a level-3 variable.
To be a bit more clear: I am fitting a longitudinal model for a panel of companies grouped in industries. I suggest that some industry variables may create 'unexpected' shocks at especific points in time; such shocks are not accounted for by the explanatory variables in the model, so that they will presumably increase variance of level-1 residuals. On the other hand, industry-level attributes may also affect the relative relative size of firm-level permanent effects (represented by level-2 residuals) Do you know how could I model such a residual structure in R? I have been looking at the varfunc command in the nlme package, but I am not sure if such a function can perform the kind of analysis I actually need. Thank you very much in advance, Antonio _________________________________________________________________ ¿Estás pensando en cambiar de coche? Todas los modelos de serie y extras en MSN Motor. http://motor.msn.es/researchcentre/ ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html