Hi,Dear Professor Wood, I am studying the generalized additive model(GAM) and I have read your related papers,especially the book named "Generalized Additive Models:An Introduction with R".I am benefit a lots.However,I also have some questions about GAM models. First,Is there some restrictions on the sample size? For example,I am studying the GDP and foreign direct investment on 29 provinces in China(N=29).Whether or not N is too samll? If so,could I use pooled data(N=29,T=5)? Second,Could I use the "mgcv" packages to implement panel data model through adding specific fixed effect and time fixed effect as the generzlied mixed model?(eg. adding factor(s)). Thanks very much in advance. Best Regards, Wanhai -- View this message in context: http://r.789695.n4.nabble.com/mgcv-tp4634305.html Sent from the R help mailing list archive at Nabble.com.