I am using a modified script for a bivariate twin analysis with two dichotomous variables.
I am stuck with the error message: "Error: In model 'Sat' I was expecting 1 thresholds in column 'nssi1' of matrix/algebra 'DZf.expThresDZf' but I hit NA values after only 0 thresholds. You need to increase the number of thresholds for 'nssi1' and give them values other than NA"
Another user had a similar issue- see previous discussion: (https://openmx.ssri.psu.edu/thread/2953). However, I do not believe my problem has to do with the mxFactor command, factors in general, or NAs in my data.
The error message implies there is something wrong with the start values I provided for the threshold ("error message... suggests that they are somehow started at NA"). I have tried a variety of different start values, but this does not seem to be the issue.
Both of my variables have incredibly low prevalence, although there are twins pairs in all groups (MZF, MZM, DZF, DZM) who are both affected (no missing cells in contingency table). Could low prevalence cause an issue with the thresholds?
Any help appreciated! Thanks.