If you don't exactly know how your classes move across time but you are pretty sure that they do in fact transition, would it possible to examine a saturated LTA model using a random half of your sample? Then, take the significant paths and confirm this model with the random second half of the sample?
If you have a large enough sample, you could randomly split it and do the analysis in both halves to see if you get the same results. I would not fix any parameters.
Lucy Barnard posted on Saturday, September 01, 2007 - 9:46 am
Is there any way to do multiple latent class analyses within the same model and then compare the results? I basically want to see if the latent class structure I observe at the first time point is stable across time.
As a first step in a latent transition analysis, you should do a latent class analysis for each timepoint to see how many classes fit the data at each timepoint. The dissertation on the website by Karen Nylund describes the steps to take to carry out a latent transition analysis. I suggest taking a look at it.
I not sure if this is a crazy question or not, but here it is. First let me say that I have cross-sectional data, but the questionnaire that Iím looking at asked participants to respond to questions related to their past body weight and physical activity behavior at multiple time points (e.g., age 20 to 25, age 15- 20). As expected this data also asks questions about current behavior. Can I use LTA to determine how participants transition from old health behavior to their current behavior? Again, sorry but Iím really not sure. Thanks
I think so, with the usual caveat about "telescoping effects".
Julia Lee posted on Saturday, June 02, 2012 - 12:25 pm
Hi Dr. Muthen,
I am using LTA mover-stayer modeling for continuous variables. Is it possible for movers to "move" within the same class for a LTA mover-stayer modeling for continous variable?
The mover and stayer means for my output are different. For 1 1 1 (movers class 1 class 1), the class count is 98.54, proportion is .18. The essential question is whether the 98 students moved (since they are classified as movers) within the same class and mixture modeling in Mplus decided that they had only "moved" within a particular threshold. Did the students make just enough improvements to remain in Class 1 but did not move to Class 2 because of a particular threshold? Conceptually, wouldn't this type of movers (e.g. 1 1 1) be considered "movers who moved within the same class" and aren't they (logically) portraying the actual stability of group membership even though 69% of the students were classified as movers? 1 1 1 98.54240 0.18914 1 1 2 0.00000 0.00000 1 2 1 56.89545 0.10920 1 2 2 162.25686 0.31143 2 1 1 56.41806 0.10829 2 1 2 0.04694 0.00009 2 2 1 0.00487 0.00001 2 2 2 146.83542 0.28183
It doesn't look like your results for movers (first class=1) indicate that they behave like movers since most stay in the same class (classes 1 1 1 and 1 2 2 are the most frequent). You don't move if you stay in the same class over time.
Julia Lee posted on Saturday, June 02, 2012 - 7:00 pm
So the classes 1 1 1 and 1 2 2, although being classified as "movers," were conceptually stayers? Then they are not any different from the stayers (i.e., Classes 2 1 1 and 2 2 2). Is it possible to have a large number of classified as movers (61%) yet, they are 1 1 1 or 2 2 2? Did I miss something? I appreciate your insight. Thank you very much.
FINAL CLASS COUNTS AND PROPORTIONS FOR EACH LATENT CLASS VARIABLE BASED ON THE ESTIMATED MODEL Latent Class Variable Class
Well, you have 10.9% in 1 2 1, so those people are moving. It is the 0% in 1 1 2 that don't want to move - perhaps going from 1 to 2 is a hard transition to make (an example would be knowing less at time 2 than at time 1). I assume that you haven't specified your model to have the constraint that nobody is in the 1 1 2 cell.
Julia Lee posted on Sunday, June 24, 2012 - 5:29 pm
Hi Dr. Bengt Muthen,
My question is regarding the LTA mover-stayer output on LATENT TRANSITION PROBABILITIES BASED ON THE ESTIMATED MODEL.
I am conducting a LTA mover-stayer with continuous variables. Is the output for the lower panel here for the movers only and hence the diagonal matrix refers to the stabiliity of the movers only (and not inclusive of the stayers' stability)? I am assuming measurement invariance. Stayers have zero probability of moving classes and movers have some probability of moving classes. I have different means for movers and stayers.
C Classes (Rows) by C1 Classes (Columns) .........1.........2 1 .......0.690...0.310 2 .......0.278...0.722 C1 Classes (Rows) by C2 Classes (Columns) .........1.........2 1....... 0.845...0.155 2....... 0.000...1.000
Hi, I was wondering whether the LTA parameterization 2 outlined in webnote 13 is equivalent to the model in Proc LTA (SAS), where x is includes as a covariate for both time 1 status and the transition probabilties?