ApolloChoiceModelling forum

Hi Georgios, I'm not sure I fully understand all your questions, but will do my best to answer. I understand you are modelling a health-related choice using latent classes, and you have data from different countries. So the country is not the dependent variable. I am not sure what you mean by the &q...

Hi, You can use the same trick for your situation, except that instead of using sociodemographics to determine the delta parameter to use in each case, you use the product category. So let's take your situation. You have 30 possible products (products 1 to 30), but in each observation a decision mak...

Hi, The delta matrix can be defined with different values for each observation in your sample. Let's start with a situation with 3 alternatives, where everyone has the same complementarity/substitution (d) parameters. You would define the delta matrix as: delta <- matrix(c( 0, 0, 0, d21, 0, 0, d31, ...

Hi, The problem is that in your code you are overwriting some components of your utility, see lines 388-392 of your code below: P[["indic_savings"]] = apollo_firstRow(apollo_ol(ol_settings5, functionality), apollo_inputs ) P[["indic_prop"]] = apollo_firstRow(apollo_ol(ol_settings...

Hi,

Please try updating the bgw package and running your model again. More specifically:

• Run the following line of code:

  Code: Select all

  install.packages("bgw")

• Then run your model again

Please let us know if this fixes the issue or not.

Best wishes
David

Hi, Sorry for the very long delay in replying. It wasn't a simple question, so it kind of got put aside for a long while. I haven't gone through the whole Bahamonde-Birke & Ortúzar paper, but I did notice that you don't include an error term in LVC1 because you mention this is essentially the de...

Hi, Yes, you can do that without issues. That way of coding the alternative would be similar to how non-labelled data from an stated choice experiment is recorded. For example, le us imagine you are modelling ice cream choice. Ice-cream is described by both flavour and price. The flavours can be van...

Hi Anat, Unlike other software, Apollo provides the user with full freedom to define the utility functions. This increased freedom, however, also means that it is the user's responsibility to make sure the model is identifiable. Let's imagine you have a model with three alternatives: A, B, and C, ea...

Hi Margrethe, If you estimate a model in preference space and do not use additional scale parameters (as the ones used in the MNL_RP_SP example), then all your parameters will have the same scale, allowing you to compare among them. However, you have to keep in mind the scale of their associated exp...

Hi Shan, Mixed logit models are much more complex than MNL models. As such, their identification is more complicated (see Walker (2002) for a detailed discussion), and there is no guarantee that your data will support a model with several random coefficients due to empirical identification issues (i...