Important: Read this before posting to this forum
- This forum is for questions related to the use of Apollo. We will answer some general choice modelling questions too, where appropriate, and time permitting. We cannot answer questions about how to estimate choice models with other software packages.
- There is a very detailed manual for Apollo available at http://www.ApolloChoiceModelling.com/manual.html. This contains detailed descriptions of the various Apollo functions, and numerous examples are available at http://www.ApolloChoiceModelling.com/examples.html. In addition, help files are available for all functions, using e.g. ?apollo_mnl
- Before asking a question on the forum, users are kindly requested to follow these steps:
- Check that the same issue has not already been addressed in the forum - there is a search tool.
- Ensure that the correct syntax has been used. For any function, detailed instructions are available directly in Apollo, e.g. by using ?apollo_mnl for apollo_mnl
- Check the frequently asked questions section on the Apollo website, which discusses some common issues/failures. Please see http://www.apollochoicemodelling.com/faq.html
- Make sure that R is using the latest official release of Apollo.
- Users can check which version they are running by entering packageVersion("apollo").
- Then check what is the latest full release (not development version) at http://www.ApolloChoiceModelling.com/code.html.
- To update to the latest official version, just enter install.packages("apollo"). To update to a development version, download the appropriate binary file from http://www.ApolloChoiceModelling.com/code.html, and install the package from file
- If the above steps do not resolve the issue, then users should follow these steps when posting a question:
- provide full details on the issue, including the entire code and output, including any error messages
- posts will not immediately appear on the forum, but will be checked by a moderator first. This may take a day or two at busy times. There is no need to submit the post multiple times.
Search found 1042 matches
- 05 May 2024, 12:07
- Forum: Model estimation
- Topic: Estimation of MNL and MMNL in WTP space issues
- Replies: 7
- Views: 3426
Re: Estimation of MNL and MMNL in WTP space issues
Apologies for the slow reply. it would be randcoeff[["b_price"]] = price_mu + price_mu * (unif_draws_a+unif_draws_b)/2 but I would advise against that distribution as the moments of WTP then do not exist. See Daly, A.J., Hess, S. & Train, K.E. (2012), Assuring finite moments for willin...
- 05 May 2024, 12:02
- Forum: Model specification
- Topic: Latent variables without demographic predictors?
- Replies: 1
- Views: 41
Re: Latent variables without demographic predictors?
Hi
yes, this is no problem.
It's not likely to be the cause for your issue. Can you show us the estimates?
Stephane
yes, this is no problem.
It's not likely to be the cause for your issue. Can you show us the estimates?
Stephane
- 05 May 2024, 12:00
- Forum: Model specification
- Topic: Latent Class Analysis with Nested Logit Model
- Replies: 8
- Views: 8597
Re: Latent Class Analysis with Nested Logit Model
Hi
apologies for the slow reply
yes, you could possibly do that
Stephane
apologies for the slow reply
yes, you could possibly do that
Stephane
- 05 May 2024, 11:51
- Forum: Errors during model validation and/or estimation.
- Topic: Unconditionals
- Replies: 13
- Views: 121271
Re: Unconditionals
apologies for the slow reply. This is very code specific, can you provide your code and data outside the forum and we can investigate
- 05 May 2024, 11:44
- Forum: Post-estimation analysis/use of results
- Topic: Difference in Marginal rate of substitution between MNL and Mixed logit models
- Replies: 1
- Views: 61
Re: Difference in Marginal rate of substitution between MNL and Mixed logit models
Hi
apologies for the slow reply
yes, this difference looks a bit too large to explain. Did you also look at the medians to see if they are reasonable (though we would want the means of course).
You might want to consider other distributions too with shorter tails
Stephane
apologies for the slow reply
yes, this difference looks a bit too large to explain. Did you also look at the medians to see if they are reasonable (though we would want the means of course).
You might want to consider other distributions too with shorter tails
Stephane
- 05 May 2024, 11:38
- Forum: Model estimation
- Topic: Covairance cannot be estimated in HCM
- Replies: 1
- Views: 45
Re: Covairance cannot be estimated in HCM
Hi
apologies for the slow reply.
Can you be more specific? Did you wait until the process has finished?
Stephane
apologies for the slow reply.
Can you be more specific? Did you wait until the process has finished?
Stephane
- 05 May 2024, 11:37
- Forum: Examples (existing and requests for new ones)
- Topic: Extending the MNL example on mode choice to MMNL
- Replies: 1
- Views: 52
Re: Extending the MNL example on mode choice to MMNL
Hi apologies for the slow reply. Using your numbering: 1) Mixed logit for random taste heterogeneity is fine. For correlation, you would be better with a nested logit or CNL kernel inside your mixture. 2) yes 3) You should not use Halton draws in that case. Try MLHS or Sobol. In relation to the sing...
- 05 May 2024, 11:33
- Forum: Estimation results
- Topic: correlation between latent variables in hybrid model
- Replies: 3
- Views: 3684
Re: correlation between latent variables in hybrid model
Hi yes, you're finding correlation. If your model estimates fine and gives you a covariance matrix, then you likely do not face an identification issue. in relation to correlation between the alternatives, I would recommend that you consider a GEV kernel such as Nested Logit instead of MNL inside yo...
- 05 May 2024, 11:31
- Forum: Model estimation
- Topic: Need Advice on Using CFA Model Results from other software with ICLV in Apollo
- Replies: 3
- Views: 93
Re: Need Advice on Using CFA Model Results from other software with ICLV in Apollo
Hi
apologies for the slow reply.
You wouldn't use factor loadings inside an ICLV model. Or what did you have in mind?
What you might want to do is to use factor analysis to determine the groupings of indicators for your latent variables
Stephane
apologies for the slow reply.
You wouldn't use factor loadings inside an ICLV model. Or what did you have in mind?
What you might want to do is to use factor analysis to determine the groupings of indicators for your latent variables
Stephane
- 05 May 2024, 11:28
- Forum: Errors during model validation and/or estimation.
- Topic: MNL - estimation failed (singular covergence)
- Replies: 1
- Views: 58
Re: MNL - estimation failed (singular covergence)
Hi
apologies for the slow reply. There is nothing immediately apparent that would be causing an overspecification. Can you tell us more about the data? Maybe there are strange correlations in the data that lead to an empirical identification issue?
Stephane
apologies for the slow reply. There is nothing immediately apparent that would be causing an overspecification. Can you tell us more about the data? Maybe there are strange correlations in the data that lead to an empirical identification issue?
Stephane