ApolloChoiceModelling forum

Nico if you look at your partial derivatives of the utility functions, you will see that they are now different for the non price attributes given that you have placed the age interaction with cost on the parameter b_price_value so now you are introducing scale heterogeneity as a function of age. On...

Hi

Yes, a ratio of two lognormals is a lognormals, and if one (and only one) of the two is a negative lognormal, then the ratio is negative lognormal too

Re your plots, are you using a low number of draws? Maybe also try without imposing the limits

Stephane

Hi

In order for us to help you, you need to show us the output, i.e. the parameter estimates.

Can you please also confirm that a MNL and mixed logit model worked on the data before moving to hybrid choice?

Thanks

Hi

first, you should always use a full set (i.e. J-1) alternative specific constants.

But is your third alternative systematically different from the other two which could lead to the issues you're seeing

Stephane

Hi

I also need to know the LL you get with MNL and in WTP space, please, i.e. where it runs out of iterations

Stephane

Hi

did you first try a model in preference space?

Stephane

1. Again, it depends on the units. Imagine that I have b_cost = -0.1 and b_time = -0.05. You can't say that cost matters more than time as it depends on the units. Imagine that cost is in € and time is in minutes. Then what the above is telling us is that €1 is more important than 1 minute, but obvi...

Hi

I think the reason your model is not working at the moment is that you only have constants in the utilities, which makes it impossible to estimate a nesting structure

Regarding your second question, can you explain a bit more what you mean, please?

Thanks

hi,

it seems like there has been an issue with that model all along as the estimates are the same across classes, so this is not a version issue

We will look into it

Stephane

Ellis your model specification is correct, as is the calculation of the beta for the reference level and the relative importance calculation (though I'm not a fan of this). But it makes no sense to calculate p values for the reference category. Think about it this way. With categorical variables, th...