ApolloChoiceModelling forum

Dear Shan it is always impossible to know a priori which parameters are the right ones in terms of allowing for random heterogeneity. It is quite possible that random heterogeneity exists for most or all your coefficients. If you only allow for random heterogeneity in some of them, you will of cours...

Hi Junghwan as discussed by Chorus & Kroesen, it is not advisable to make a change to the latent attitude in forecasting as the scale of this arbitrary. So e.g. a 10% increase is not a meaningful concept. What we did in the 2018 paper is to look at a situation where everyone adopted the attitude...

Hi Dominik so what you are doing here is to allow for differencesin the value for the ASCs and the marginal utility coefficients as a function of the condition. That's the right thing to do. When you allow for differences in all terms, then this is equivalent to estimating two separate models, but y...

Hi Sara

you need to install from the binaries rather than the soruce file

Best wishes

Stephane

Hi Sara

you need to use / instead of \

It is also possible to do this via the menu in RStudio (tools-install packages) which will make it easier for you

Stephane

Hi apollo_prediction uses only the posterior means, so I would be very careful in using it in the situation where some of your marginal utility parameters are actually given by sums of multiple model parameters. Even if that wasn't the case, you should be very careful with using posterior means as t...

Hi Eduardo

you have included the same terms in both utilities, so the model is not identified. Apollo is telling you that b_female (the first parameter it tries) cannot change the log-likelihood as it influences both utilities in the same way.

Best wishes

Stephane

Hi 1. Your model is simply combining a number of different ordered logit models. You are not making any links between these components, so I wouldn't really refer to it as multivariate. If you want to create links between the models, you could incorporate a latent variable, for example. 2. The funct...

Hi Apollo relies on RSGHB for Bayesian estimation, and the posteriors are for each individual coefficient rather than an addition or other transformation involving multiple coefficients. With Normals, you could add up the posterior means, but would you really want to use a Normal for price anyway? W...

Hi Raffaele is this simply a case of you trying to run the whole file in one go? Try running it only to the estimate line, then it will prompt you to confirm whether you want to proceed with estimation - see the Estimate Model? (Y/N) prompt in your output. If you were running the whole file in one g...