Josie Booth posted on Wednesday, July 07, 2010 - 3:57 am
I'm carrying out mulit-group SEM and looking for a bit of advice please. I have metric and scalar invariance and have compared the latent means of the two groups. In addition to this I would like to assess whether the regression weights for the structural paths are the same or not. I get a significant delta chi-square when I compare the model with the paths constrained to be equal to one where they are free. I have then freed each path individually while constraining the others to be equal. I get a significant delta chi-square every time but when I look at the regression weights for each group they are overlapping (using 1.96xSE) thus suggesting that they don't actually differ. I'm aware that the significant change to the chi-square could be due to the totality of the changes made by freeing just one parameter but I'm unsure as to the conclusions which can be drawn.
Firstly, is my logic correct and if so can I conclude that the paths are the same between groups? Secondly, is there a more appropriate way of assessing this?
In addition when all paths are free, I get extremely large standard errors for one group (Est 10.57, SE 14.36 & Est 12.71, SE 15.28). Should I be concerned about the size of these SE's? When looking at the standardised solution these SE's are greater than one - is this acceptable?
You can instead make a path equal across the groups while letting the other paths be different across groups.
If SEs for one group are much larger without its sample size being much smaller, I would do a separate analysis of this group to see if the SEs are large then also.
Josie Booth posted on Thursday, July 08, 2010 - 7:25 am
Thank you very much for your help.
I have done a separate analysis for each group and the standard errors are much more appropriate. I wonder if you could possibly advise as to why it makes such a difference to the standard errors estimating the two groups in the same or different analysis?