R help - Apr 2013 - lavaan and semTools warning message

Hello all,

I am running a simple path analysis with the function sem.mi (of semTools)
after doing multiple imputation in my (missing) data. However, depending on
the option to combine the chi-square, I get the following warning messages:

Warning messages:
1: In estimateVCOV(lavaanModel, samplestats = lavaanSampleStats,  ... :
  lavaan WARNING: could not compute standard errors!

2: In pchisq(chisq, df) : NaNs produced
3: In estimateVCOV(lavaanModel, samplestats = lavaanSampleStats,  ... :
  lavaan WARNING: could not compute standard errors!

4: In pchisq(chisq, df) : NaNs produced
5: In estimateVCOV(lavaanModel, samplestats = lavaanSampleStats,  ... :
  lavaan WARNING: could not compute standard errors!

and so forth.

The options chi="mr" and "mplus" result in these warning
messages, but
options chi="lmrr" and "none" run fine (no warning
messages). Even when I
get these warning messages, all estimates (including se and chi) are
printed out in the results (using summary, for example).

Also, using the function sem (of lavaan package) directly (with one of the
"replicated" datasets) runs fine.


Here is the code I'm using:

# start code

# model syntax
model1 <- '
    # regressions

    r1 ~ p1+p2+p3+p4+p5+p6+p7+p8+p9+p10+p11
    r2 ~ r1+p2+p4+p5+p6+p8+p9+p10+p11+p12+p13+p14
'

# run sem (N=124); data are already imputed
out1 <- sem.mi(model1,imputedData,m=20,chi="mr",fixed.x=T,std.ov=T)
summary(out1)
inspect(out1, "imputed") # the combined chi is presented

# end code


Can someone tell me why am I getting these warning messages?

Thanks,

Duarte

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