The model you have specified there is not an ordinary factor analysis model.
This may be closer to what you are thinking of: model.RLIM <- specify.model() f1 -> R, laddR, NA f1 -> L, laddL, NA f1 -> I, laddI, NA f1 -> M, laddM, NA R <-> R, dR, NA L <-> L, dL, NA I <-> I, dI, NA M <-> M, dM, NA f1 <-> f1, NA, 1 sem.RLIM=sem(model.RLIM,tcv,101) summary(sem.RLIM) Note that the paths go from the latent factor to the manifest variables, not vice-versa. Best, -- Wolfgang Viechtbauer http://www.wvbauer.com/ Department of Methodology and Statistics Tel: +31 (0)43 388-2277 School for Public Health and Primary Care Office Location: Maastricht University, P.O. Box 616 Room B2.01 (second floor) 6200 MD Maastricht, The Netherlands Debyeplein 1 (Randwyck) ________________________________________ From: r-help-boun...@r-project.org [r-help-boun...@r-project.org] On Behalf Of Ralf Finne [ralf.fi...@novia.fi] Sent: Wednesday, November 25, 2009 5:23 PM To: r-help@r-project.org Subject: [R] Structural Equation Models(SEM) Hi R-colleagues. In the sem-package i have a problem to introduce hidden variables. As a simple example I take an ordinary factor analysis. The program: cmat=c(0.14855886, 0.05774635, 0.08003300, 0.04900990, 0.05774635, 0.18042029, 0.11213013, 0.03752475, 0.08003300, 0.11213013, 0.24646337, 0.03609901, 0.04900990, 0.03752475, 0.03609901, 0.31702970) rn=c("R","L","I","M") cn=c("R","L","I","M") tcv=matrix(cmat,nrow=4,ncol=4,dimnames=list(rn,cn)) model.RLIM <- specify.model() R -> f1, laddR, NA L -> f1, laddL, NA I -> f1, laddI, NA M -> f1, laddM, NA R <-> R, dR,NA L <-> L, dL,NA I <-> I, dI,NA M <-> M, dM,NA f1 <-> f1, df1,NA sem.RLIM=sem(model.RLIM,tcv,101) The output: Error in dimnames(x) <- dn : length of 'dimnames' [2] not equal to array extent In addition: Warning messages: 1: In sem.default(ram = ram, S = S, N = N, param.names = pars, var.names = vars, : singular Hessian: model is probably underidentified. 2: In sem.default(ram = ram, S = S, N = N, param.names = pars, var.names = vars, : refitting without aliased parameters. I use R version 2.10.0 (2009-10-26) under Windows XP sem_0.9-19 version. Where did I make a mistake? Have anyone of you knowledge of any other package doing similar things like Confirmative Factor Analysis Ralf Finne Novia University of Applied Science Vasa Finland ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
