Chris Weber posted on Thursday, December 05, 2013 - 9:44 am
I am estimating a simple mover stayer model with a three category variable measured at five time points. Since the latent classes for each of the five waves is measured with a single variable, I constrain the item thresholds. Yet, I get the following error for each class: *** ERROR in MODEL command One or more pairs of ordered thresholds are not increasing in Class 1. Check your starting values. Problem with the following pairs: PID_1$1 (15.000) and PID_1$2 (-15.000) PID_2$1 (15.000) and PID_2$2 (-15.000) ..... Any tips on how to do this?
Clases are specified as follows: classes= c(2) c1(3) c2(3) c3(3) c4(3) c5(3); !c is mover stayer
At the end of the file, I constrain the thresholds for each of the three classes within the five latent variables (t1-t5). This generates the error. For instance:
I am trying to estimate a LTA mover-stayer model as per example 8.15. I had the same issue as above when attempting to constrain for equality (ordered thresholds not increasing), and was able to run the model by changing:
%c1$1% [c1_est$1] (1)
%c1$1% [c1_est$1@-15] (1)
Is this the correct way to specify the order of the threshold values? c1_est contains 5 classes: is it acceptable to specify only the first threshold, or do I need to specify the threshold for each class?