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 8 matches
- 13 Nov 2022, 00:30
- Forum: Model estimation
- Topic: negative standard errors of random coefficients
- Replies: 1
- Views: 3774
negative standard errors of random coefficients
I estimated a mixed logit model with three random coefficients (log-normal distributed). see below: mu_log_b_prm -5.59949 sigma_log_b_prm -1.86121 mu_log_b_sub -9.10539 sigma_log_b_sub -4.87119 mu_log_b_lia -8.49144 sigma_log_b_lia 3.91300 Are these valid estimates?
- 10 Nov 2022, 02:53
- Forum: Model specification
- Topic: nonlinear utility function
- Replies: 1
- Views: 1026
nonlinear utility function
I am trying to estimate a mixed logit model with a non-linear utility function (with risk preference parameters to identify).
Does Apollo allow me to specify and estimate a non-linear utility function?
Does Apollo allow me to specify and estimate a non-linear utility function?
- 01 Feb 2022, 16:29
- Forum: Model specification
- Topic: latent class model
- Replies: 2
- Views: 2698
latent class model
Hi Stephane, I am trying to specify a latent class model. But the class is not fixed for each individual over time. In other words, starting from one period, an individual's situation is changed, his status/group is changed. In model specification, I want to include not only individual demographic v...
- 16 Jan 2022, 18:53
- Forum: Errors during model validation and/or estimation.
- Topic: Error after convergence when estimating a latent class model
- Replies: 1
- Views: 2203
Error after convergence when estimating a latent class model
Hi, First, thank you for all your help along the process. You have been answering several questions quickly, very helpful. Much appreciated! the model runs and converged after 59 iterations, but some error message appears after that saying: "Error in maxOptim(fn = fn, grad = grad, hess = hess, ...
- 11 Jan 2022, 20:34
- Forum: Errors during model validation and/or estimation.
- Topic: error in estimating a latent class model
- Replies: 1
- Views: 2132
error in estimating a latent class model
Hi, I am estimating a latent class model. In estimation the following error message poped up: "Testing influence of parameters Error in apollo_avgInterDraws(P[["model"]], apollo_inputs, functionality) : No Inter-individuals draws to average over!" I appreciate your suggestions! I...
- 04 Jan 2022, 21:20
- Forum: Errors during model validation and/or estimation.
- Topic: log-likelihood calculation failed
- Replies: 1
- Views: 2137
log-likelihood calculation failed
Hi, I am estimating a mixed logit model with 3 random coefficients and got the following error message: "Error in apollo_estimate(apollo_beta, apollo_fixed, apollo_probabilities, : Log-likelihood calculation fails at values close to the starting values!" I tried to use the logit estimates ...
- 16 Dec 2021, 14:37
- Forum: Data preparation, processing and pre-estimation analysis
- Topic: difference choice sets
- Replies: 2
- Views: 5535
Re: difference choice sets
Thanks a lot, Stephanehess! I will take a careful look and get back to you if I have questions.
- 13 Dec 2021, 18:12
- Forum: Data preparation, processing and pre-estimation analysis
- Topic: difference choice sets
- Replies: 2
- Views: 5535
difference choice sets
In my case, for each choice situation, the choice set is slightly different, in other words, some alternatives are not available. So if I change to "wide" format, some alternative-specific attributes are NA. Can I still use Apollo to estimate the model? Thanks!