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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? Many thanks, Lucy Barnard 


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. 


Hi, I not sure if this is a crazy question or not, but here it is. First let me say that I have crosssectional data, but the questionnaire that I’m 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 I’m 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 moverstayer modeling for continuous variables. Is it possible for movers to "move" within the same class for a LTA moverstayer 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 Thank you in advance. Julia 


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 C......... 1 317.69470 0.60978 .......... 2 203.30531 0.39022 C1.........1 155.00745 0.29752 ...........2 365.99255 0.70248 C2.........1 211.90700 0.40673 ...........2 309.09302 0.59327 


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 moverstayer output on LATENT TRANSITION PROBABILITIES BASED ON THE ESTIMATED MODEL. I am conducting a LTA moverstayer 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 I appreciate your response. Thank you. 


No, it is for both the movers and the stayers. 


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? i.e. in SAS Proc LTA PROC LTA DATA= ; NSTATUS ; NTIMES 2; ITEMS u11 u12 u13 u14 u21 u22 u23 u24; CATEGORIES 2 2 2 2; SEED 123456; Covariates1 x; Covariates2 x; RUN; Thanks, O 


Please send/point to documentation that shows the PROC LTA parameterization. 


Hi Bengt, The Proc LTA parameterization details are at http://methodology.psu.edu/downloads/proclcalta in the User's Guide. Thankyou. 


Please point to a specific document and a specific page. 


Sorry, document is the User's Guide v 1.2.7, pages 78 


Yes, it looks like the Mplus parameterization 2 of Web Note 13 is the same as used in Proc LTA. 

Jane Smith posted on Wednesday, March 05, 2014  7:45 am



Drs. Muthen, I've run an LTA with a second order effect, an interaction and a covariate, and am trying to interpret the transitions. Specifically, how are the transitions under 'LATENT TRANSITION PROBABILITIES BASED ON THE ESTIMATED MODEL' different than those given by the LTA calculatorwhich I know are based on the levels of the covariates. In other words, how are the covariates/interaction allowed to influence the estimated model transitions? I've read webnote 13, but am unable to resolve my question. 


Please send the output and your license number to support@statmodel.com. 

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