However, I've looked through the user manual and it doesn't seem to be an option. The truncated negative-binomial seems to the only option available for a zero-truncated count model. Is that correct? Have I overlooked something?
You can fix the alpha dispersion parameter of negbin to a small value to approximate Poisson. Like 0.01.
Daniel Lee posted on Thursday, March 12, 2020 - 7:48 am
Hi Dr. Muthen,
I ran a zero-truncated negative binomial model. I am trying to get incident rate ratios (IRRs). Is it OK to run the following model constraint command to obtain these rates (by exponentiating the coefficients):
Daniel Lee posted on Friday, March 13, 2020 - 10:59 am
I own a copy of the regression and mediation analysis using Mplus book. While there is some mention of the zero-truncated negative binomial model, it is within the context of a two-regression hurdle model.
Does the analysis become a zero-truncated negative binomial regression, if in table 6.5 (page 270), I remove the following code from Model command (while keeping "naffairs ON kids-yrsmarr6"):
No, you should instead look at Table 6.7 in our book and the text on page 272 that goes with it.
Daniel Lee posted on Saturday, March 14, 2020 - 7:38 pm
Hi Dr. Muthen,
In page 272, a hurdle model was estimated that specifies one process for zero counts and another process for positive counts. In my data, the value zero cannot occur. Hence, I thought that the following syntax would be correct:
Usevariable: Names = y x1 x2; Usevar = y x1 x2; Count = y(NBH);
Model: y ON x1 x2;
Relative to Table 6.7, I removed the following code (y#1 on x1 x2) because this specifies a logistic regression for the binary outcome being greater than zero.
Please let me know if I am interpreting/comprehending something incorrectly in the book. Again, I very much appreciate your help.