I expect I can account for clustering by using lme with clusters as a random effect, but then I can't use the flexible smooths available in gam.
If it's not possible to get both clustering and smooths, I may use gam and adjust the standard errors using an estimate of the design effect.
Many thanks for any advice, Paul
Paul von Hippel Department of Sociology / Initiative in Population Research Ohio State University
______________________________________________ [EMAIL PROTECTED] mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html