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OL with latent classes

Ask questions about existing examples and put in requests to software developers and users for other example implementations of models.
MAF
Posts: 9
Joined: 16 Nov 2020, 17:27

Re: OL with latent classes

Post by MAF »

Thank you for the tip Stephane, I looked at example 21 and later changed the parameters and a few things and it works now when combining a MNL model and an OL model using latent classes. It also works with just a simple MNL model and latent classes. Though, I cannot make it work with just a simple OL model and latent classes. Is the latter not possible to estimate given the assumptions of OL? Or I am doing something wrong? Thanks !
MAF
Posts: 9
Joined: 16 Nov 2020, 17:27

Re: OL with latent classes

Post by MAF »

Just to clarify, I am asking about a simple OL with latent classes because I am still intrigued by the sentence in the Apollo manual, page 75, " the Tau parameters can vary across classes". I interpret this as the Taus being a function of one class at the time, and the modeler can choose the class, right? Or should I read it as "taus can vary as a function of two or more classes"? Also, I am trying to get the simplest possible model with OL and latent classes so I can understand its behavior before adding more components. I hope this makes sense.
stephanehess
Site Admin
Posts: 974
Joined: 24 Apr 2020, 16:29

Re: OL with latent classes

Post by stephanehess »

sorry, it's really difficult for us to answer your question as it's not very clear what you're asking.

Parameters that are used inside apollo_probabilities can vary across classes. That includes the thresholds in an ordered logit model just like the marginal utility parameters in other models.

When you say "I interpret this as the Taus being a function of one class at the time, and the modeler can choose the class, right? Or should I read it as "taus can vary as a function of two or more classes"?", it's really not clear what you are meaning. The modeller doesn't choose the class, the classes are latent.

I assume (and please confirm) that what you are wanting to do is the following:

1. your choice model inside each class would be an ordered logit model, with the parameters of that OL, including the thresholds, being class specific
2. you have a latent class structure, and you would use an MNL model for the class allocation

Step 1 happens inside apollo_probabilities, but the parameters for classes are described in apollo_lcPars. Step 2 happens in apollo_lcPars

Again, if you could be more specific with what it is you're trying to do, explaining it for your data, for example, then we can help you
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Stephane Hess
www.stephanehess.me.uk
MAF
Posts: 9
Joined: 16 Nov 2020, 17:27

Re: OL with latent classes

Post by MAF »

Thank you, I went back to the examples and after a few tests I realized I was not properly using the functions the calculate and use the pi_values. Miguel
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