This means that the bivariate frequency table for SZOID1 AND PARND6 has an empty cell which implies a correlation of one. Both of these variables cannot be used in the analysis. You can combine them into one variable with three categories, for example, observations with 0 0 can be assigned 0 on the new variable, those with 0 1 can be assigned 1 and those with 1 1 can be assigned 2.
I've been continuing to work on this issue and better understand it. I was also given the following advice:
"But how's about you try the model again, with the logit (with the ML or MLR estimator) rather than the probit link function (with the least squares family) for the regressions of the items on the factors? Correlations (moments) aren't used for this, so maybe the same problem wouldn't arise."
My understanding is that the logit and probit link is used with ML estimation in Mplus. Can this also be done with the least squares family?
Thank you Linda! Would you have an idea why this simulation would not work. The error and program are below. The program is taken exactly from page 343 of the Mplus manual (Example 11.5). I have tried several modifications to the program to get it to work to no avail. I have the required computer parameters and all the latest updates for Mplus.
Mplus VERSION 5.1 MUTHEN & MUTHEN 06/05/2008 3:28 PM
montecarlo: names are y1-y6; nobservations=500; nreps = 10; seed=45335; model population: f1 BY y1-y3*.7; f2 BY y4-y6*.8; f1-f2@1; f1 WITH f2*.5; y1-y3*.51; y4-y6*.36; ANALYSIS: TYPE = EFA 1 2; OUTPUT: TECH9;
INPUT READING TERMINATED NORMALLY
*** FATAL ERROR THERE IS NOT ENOUGH MEMORY SPACE TO RUN Mplus ON THE CURRENT INPUT FILE. YOU CAN TRY TO FREE UP SOME MEMORY BY CLOSING OTHER APPLICATIONS THAT ARE CURRENTLY RUNNING. NOTE THAT THE MODEL MAY REQUIRE MORE MEMORY THAN ALLOWED BY THE OPERATING SYSTEM. REFER TO SYSTEM REQUIREMENTS AT www.statmodel.com FOR MORE INFORMATION ABOUT THIS LIMIT.
We did not remove EFA. We removed the error message. There are probelems with EFA and Monte Carlo because for some models the factors may not keep the same order across replications which renders the results averaged over replications meaniningless. A better approach is specifying EFA in the MODEL command a feature which was added in Version 5.1. The ordering issue has been addressed for this case although improvements will be made in the next update. See the Version 5.1 Language and Examples Addendum on the website with the user's guide.
I have a nominal variable in my dataset (independent variable). As there are 3 categories in the nominal variable, I have created 2 dummy variables(taking 0,1 values each) instead. I get this warning:
WARNING: THE SAMPLE CORRELATION OF SERV_DUM AND PROD_DUM IS -0.989 DUE TO ONE OR MORE ZERO CELLS IN THEIR BIVARIATE TABLE. INFORMATION FROM THESE VARIABLES CAN BE USED TO CREATE ONE NEW VARIABLE.
This is because I have no values which are both 1. Is there a way to get away with this? By creating 2 dummy variables for a 3 category variable implies that I will not have cases with both a value of 1. Thanks in advance