ApolloChoiceModelling forum

May I ask what you would do? Go for the loguniform distribution, as in this case, all parameters are random? Or would you model the "frequency" attribute as a fixed parameter to get around the problem with a sizable probability mass around zero?

Yes, I worry about the signs. It's like estimating utility for charities: Respondents don't really like giving money away, but like the feeling of doing something good. In my case, it is a study on the constraints on the use of air conditioning in office buildings and the attribute "frequency&q...

I've just tried to specify my first RRM model within Apollo and everything seems fine, except for the alternative-specific constants (ASCs). The specification is based on the RRM example on the Apollo homepage. The following statement can be found in the manual on page 51: For the alternative specif...

Hello everyone, I need your advice on a MIXL model where a lot of probability mass is close to zero. My MIXL model has five attributes with multiple attribute levels each. Two attributes are continuous and negative, i.e., with increasing levels utility is supposed to decrease. However, these attribu...

Hi guys, Thanks for the quick reply. I am aware that with Bayesian estimation the calculation of the log-likelihood function is only point-wise. But this is exactly what I was looking for: If I understood it correctly, to calculate the WAIC, I have to sample from the posteriori distribution and calc...

Helle Stephane, hello David, I have a question regarding apollo_llCalc in Bayesian estimation. I have a model with two components, both of them are MNL models. Whenever I try to run the function apollo_llCalc I get the following error message: Calculating LL of each model component...Not applicable ...

Hi Stephane, Thank you very much for your answer and the articles. I already knew the one with Kenneth Train, but not the other from 2012. The problem is the more sophisticated the model, the higher its complexity. For example, when I want to "[...] test the model against one that allows for di...

Dear Stephane, Unfortunately, I have another question about the scale parameter in dual response: Does it make sense to use a randomized scale parameter (e.g. lognormal distribution or lognormal distribution with Fosgerau Mabit transformation) instead of a fixed parameter? The reason is that I wish ...

Yes, exactely. In the forced-choices (3 alternatives per choice set) I check for left-right effects (b_asc_1, b_asc_2, b_asc_3), whereas in the free choices, I would like to explain the responses to the Likert scale questions. About the scale parameter: Does it matter if I multiply only the coeffici...

Thank you for the fast response. In the following, as requested the code of the two MNL models. Ordinal: # ################################################################# # #### LOAD LIBRARY AND DEFINE CORE SETTINGS #### # ################################################################# # ### Cle...