R help - May 2013 - SEM: multigroup model

Dear R Gurus,

I am trying to run a multigroup SEM using Prof. John Fox's SEM package.

The two groups are "Ready to Eat" denoted by RTE and
                            "Ready to Cook" denoted by RTC.

I ran a omnibus CFA on the data of consumer perceptions & preferences and
am satisfied with what I got.

When I tried to do a multigroup SEM - my understanding is limited to the
SEM manual in CRAN - using the code below, I get the following message:
          Error in summary.msemObjectiveML(sem.MG) :
                         no 'dimnames' attribute for array
           Execution halted

The relevant part of my code follows:
mod.mg <-
multigroupModel(sbmod.cfa,groups=c("RTC","RTE"))

sem.MG <- sem(mod.mg,data=srt,group="RTind",
          formula = ~ inv + imp + tch + emo + loy + usg + sig + dif + ndif
+
            vda + vdb + vdc + vdd + vde + vdf + vdg + vdh +
            riskT + riskP + riskS + riskFi + riskFu + riskPs

        )
summary(sem.MG)

I was expecting two sets of fit indices for RTE & RTC and want to do an
ANOVA
across the models; as well as possibly check for loading equivalence.

Can somebody please throw some light on where I am making a mistake?

Thanks
Amarnath Bose
-- 


    *Amarnath Bose*
* **Associate Professor                       *
*Decision Sciences Department*
*Birla Institute of Management Technology
*
Tel:  +91 120 2323001 - 10 Ext.: 398
Cell: +91 9873179813

	[[alternative HTML version deleted]]

Dear Amarnath Bose,

There's nothing obviously wrong with the commands that you report -- in
fact, your commands have the same structure as the multigroup SEM example in
?sem -- so the usual advice about including reproducible code producing the
error applies. If you like, you could send me your data and the complete R
script that you used.

Best,
 John

-----------------------------------------------
John Fox
Senator McMaster Professor of Social Statistics
Department of Sociology
McMaster University
Hamilton, Ontario, Canada


> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Amarnath Bose
> Sent: Thursday, May 23, 2013 6:54 AM
> To: r-help at r-project.org
> Subject: [R] SEM: multigroup model
> 
> Dear R Gurus,
> 
> I am trying to run a multigroup SEM using Prof. John Fox's SEM package.
> 
> The two groups are "Ready to Eat" denoted by RTE and
>                             "Ready to Cook" denoted by RTC.
> 
> I ran a omnibus CFA on the data of consumer perceptions & preferences
> and
> am satisfied with what I got.
> 
> When I tried to do a multigroup SEM - my understanding is limited to
> the
> SEM manual in CRAN - using the code below, I get the following message:
>           Error in summary.msemObjectiveML(sem.MG) :
>                          no 'dimnames' attribute for array
>            Execution halted
> 
> The relevant part of my code follows:
> mod.mg <-
multigroupModel(sbmod.cfa,groups=c("RTC","RTE"))
> 
> sem.MG <- sem(mod.mg,data=srt,group="RTind",
>           formula = ~ inv + imp + tch + emo + loy + usg + sig + dif +
> ndif
> +
>             vda + vdb + vdc + vdd + vde + vdf + vdg + vdh +
>             riskT + riskP + riskS + riskFi + riskFu + riskPs
> 
>         )
> summary(sem.MG)
> 
> I was expecting two sets of fit indices for RTE & RTC and want to do an
> ANOVA
> across the models; as well as possibly check for loading equivalence.
> 
> Can somebody please throw some light on where I am making a mistake?
> 
> Thanks
> Amarnath Bose
> --
> 
> 
>     *Amarnath Bose*
> * **Associate Professor                       *
> *Decision Sciences Department*
> *Birla Institute of Management Technology
> *
> Tel:  +91 120 2323001 - 10 Ext.: 398
> Cell: +91 9873179813
> 
> 	[[alternative HTML version deleted]]
> 
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