It should be random=~1|FAM/ID indicating individuals are nested within families. -----Original Message----- From: r-help-bounces at stat.math.ethz.ch [mailto:r-help-bounces at stat.math.ethz.ch] On Behalf Of Federico Calboli Sent: Wednesday, March 23, 2005 12:34 PM To: Shaw, Philip (NIH/NIMH) Cc: r-help Subject: Re: [R] nested random effects
On Wed, 2005-03-23 at 11:58 -0500, Shaw, Philip (NIH/NIMH) wrote:
Hi I am struggling with nested random effects and hope someone can help. I have individuals (ID) who are nested within families (FAM). I want to model an outcome variable, and take account of the intercorrelation
of individuals within each family. I think this amounts to two random effects, one nested within the
other.
How can I model this in R? So far I have tried using the library(nlme), and then Y~ID, random=~1|ID*FAM,
An interaction random effect/fixed effect is noted as random ~1|random/fixed in your case random =~1|ID/FAM (but I don't uderstand why indiviuals withing families are fixed and and families are random, but there you go). Check out Pinheiro and Bates Ch1, especially pg 23 onwards. Cheers, F
Federico C. F. Calboli Department of Epidemiology and Public Health Imperial College, St Mary's Campus Norfolk Place, London W2 1PG Tel +44 (0)20 7594 1602 Fax (+44) 020 7594 3193 f.calboli [.a.t] imperial.ac.uk f.calboli [.a.t] gmail.com ______________________________________________ R-help at 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