Mon, 11/11/2013 - 22:43

Dear Dr mike :

I have a question about MASEM. My example is to study the effect of social support on depression.I found four variables : subject support (zz), objective support (kz) , the using of support (zl), depression (yy). Among these , zz, kz, zl were loaded under a higher-order factor ,called "Alpha", that represents social support. The following is my R code :

a<-c(1,0.428,0.41,-0.327,0.428,1,0.292,-0.199,0.41,0.292,1,-0.198,-0.327,-0.199,-0.198,1)

m1<-matrix(a,nrow=4,ncol=4,dimnames=list(rowname,colname))

rowname=c("zz","kz","zl","yy")

rowname

colname=c("zz","kz","zl","yy")

colname

m1

b<-c(1,0.482,0.239,-0.183,0.482,1,0.305,-0.229,0.239,0.305,1,-0.256,-0.183,-0.229,-0.256,1)

m2<-matrix(a,nrow=4,ncol=4,dimnames=list(rowname,colname))

rowname=c("zz","kz","zl","yy")

rowname

colname=c("zz","kz","zl","yy")

colname

m2

c<-c(1,0.474,0.360,-0.044,0.474,1,0.42,-0.113,0.360,0.42,1,-0.185,-0.044,-0.113,-0.185,1)

m3<-matrix(c,nrow=4,ncol=4,dimnames=list(rowname,colname))

rowname=c("zz","kz","zl","yy")

rowname

colname=c("zz","kz","zl","yy")

colname

m3

d<-c(1,0.330,0.294,-0.246,0.330,1,0.261,-0.264,0.294,0.261,1,-0.217,-0.246,-0.264,-0.217,1)

m4<-matrix(d,nrow=4,ncol=4,dimnames=list(rowname,colname))

rowname=c("zz","kz","zl","yy")

rowname

colname=c("zz","kz","zl","yy")

colname

m4

e<-c(1,0.25,0.24,-0.21,0.25,1,0.15,-0.19,0.24,0.15,1,-0.23,-0.21,-0.19,-0.23,1)

m5<-matrix(e,nrow=4,ncol=4,dimnames=list(rowname,colname))

rowname=c("zz","kz","zl","yy")

rowname

colname=c("zz","kz","zl","yy")

colname

m5

l1<-list(m1,m2,m3,m4,m5)

l2<-list(A=m1,B=m2,C=m3,D=m4,E=m5)

names(l2)

l2

n<-c(211,123,459,698,310)

n

#### Load the metaSEM library for TSSEM

library(metaSEM)

#### Inspect the data for inspection

head(l2)

head(n)

#### Fixed-effects model: Stage 1 analysis

fixed1 <- tssem1(my.df=l2, n=n, method="FEM")

summary(fixed1)

coef(fixed1)

I didn't know how to specify, so I could't go on . I look forward to reading your responses. Thank you!

regards,

xiarizhiyue0727

Hi xiarizhiyue,

The Stage 2 specification uses the RAM specification (McArdle & McDonald, 1984) that is also used by OpenMx.

There are several examples in OpenMx:

http://dbtemp.blogspot.sg/2011/08/structural-equation-modeling-in-openmx...

http://openmx.psyc.virginia.edu/docs/OpenMx/latest/Examples_Matrix.html

In metaSEM, there are several examples in the help manual. You may refer to the "See Also" section in the help of tssem1(). There are also examples in the following paper: https://dl.dropboxusercontent.com/u/25182759/Fixed%20and%20random%20effe...

http://courses.nus.edu.sg/course/psycwlm/Internet/metaSEM/masem.html

http://courses.nus.edu.sg/course/psycwlm/internet/metaSEM/metasem.pdf

McArdle, J. J., & McDonald, R. P. (1984). Some algebraic properties of the Reticular Action Model for moment structures. British Journal of Mathematical and Statistical Psychology, 37(2), 234–251. doi:10.1111/j.2044-8317.1984.tb00802.x

Hope it helps.

Regards,

Mike