ApolloChoiceModelling forum

Hi Stephane, Thank you for your reply. I agree that the positive cost coefficient is a bit worrying. Indeed, the cost is negative but not significant in the simplest MNL preference-space model (model 1). For the MNL WTP-space model, I did try a negative starting value for the cost parameter, but the...

Dear Stephane, Thank you very much for inventing the Apollo. I’m also the attendees of your previous summer and winter DCE courses. I was estimating a MMNL WTP space model and had a problem. The DCE Attributes: h (health, number hospital admissions due to air pollution), v (number of bad visibility ...

Dear Stephane, I was estimating a RPL model with a non-linear specification in one of the attributes. The DCE Attributes: air, flood, ObjCert, largetrees, mixedtrees, cost Available options: 2 alternatives + 1 status quo The model The nonlinear part is specified as: R*=(exp(-((-log(R))^gamma)))), wh...

Hi Stephane, Thank you for the solution. I actually wanted to ask a similar question regarding different results obtained from preference-space and WTP-space approach, but your solution solves my problem quite well. Actually, the above problem happens in my situation even when I use the most basic M...

Hi Stephane,

Thank you very much for your email and David's solution. Also thank you for reminding me reading the corresponding section in the manual which actually helps to solve my problem.

Thank you again.

Best wishes,
Tim

Dear Stephane, Thank you vey much for your help. The model runs successfully, but the standard errors for all parameters are "Inf". This actually happened before when I was running some complex models (e.g., imposing complex distributions such as Johnson SB distribution or polynomial-norma...

Dear Stephane and David, Thank you very much for inventing the Apollo package and creating the forum allowing our users to communicate. I recently run a latent class model, but allow for inter-individual heterogeneity only within one of the classes (i.e., preferences are assumed to be non-random in ...

Dear Stephane, Yes I had errors when running apollo_inputs = apollo_validateInputs(), but I have solved the problem; it was a small mistake - I forgot to turn on the mixing=TRUE at the start. I can confirm that the non-linear specification can be run successfully using MMNL. Thank you again for your...

Dear Stephane, Thank you for inventing the Apollo package and answering my past questions. I have encountered an error when estimating a nonlinear utility specification using MMNL. Description of my model: I have a health attribute (h) and a probability attribute (p) associated with the health outco...

Hi Stephane,

Thanks a lot for your responses.

Tim