Path analysis failing to converge

[Ava Buxton]

Hello all!

I am conducting a path analysis X->M->Y->Y2, with paths from:
X->M (a)

M->Y (b)

X->Y (c)

Y->Y2 (d)

X and M are continuous. Y and Y2 are binary (0/1).

This is my model:

model <- '
  M ~ a*X
  Y ~ b*M + c*X
  Y2 ~ d*Y
  ab := a*b
  total := c + ab
  '

This is my current code for fitting the model:

fit <- sem(model, data = data, se = "bootstrap", bootstrap = 5000, iseed = 1)

And then for viewing the results:
summary(fit, fit.measures = TRUE, standardized = TRUE, rsquare = TRUE)

I saw that for dealing with categorical/binary variables, I need to include ordered = c("Y", "Y2") and estimator = "DWLS" when fitting.

I attempted this, but the model did not "converge". When inquiring, I found the Y/Y2 may be too associated, which may have caused this. The variables are similar, so this might make sense. Could this be it, or may there be another reason? Should I change the arguments I am using or add new ones? I saw another user on a forum who suggested including parameterization = "theta". Would this make sense to include?

Thank you!

Ava