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 998 matches
- 25 May 2020, 22:30
- Forum: Errors during model validation and/or estimation.
- Topic: ICVL Model Identification issues
- Replies: 3
- Views: 6270
Re: ICVL Model Identification issues
Hi it's of course difficult to diagnose the problem without access to the data, but this looks at first hand like an identification issue. The zeta parameter becomes very large for one indicator while the taus become very wide too. I noticed that you used a different specification for the structural...
- 23 May 2020, 21:10
- Forum: Model specification
- Topic: How to choose random parameters for MMNL model
- Replies: 3
- Views: 5945
Re: How to choose random parameters for MMNL model
Hi Shan
yes, you should be able to make those parameters non-random where the standard deviations are not significant. Keep an eye on your model fit too to see if you're not losing fit by doing so
Best wishes
Stephane
yes, you should be able to make those parameters non-random where the standard deviations are not significant. Keep an eye on your model fit too to see if you're not losing fit by doing so
Best wishes
Stephane
- 23 May 2020, 21:07
- Forum: Post-estimation analysis/use of results
- Topic: Estimating the average marginal effects of a mixed logit within Apollo's post-estimation functions?
- Replies: 2
- Views: 5431
Re: Estimating the average marginal effects of a mixed logit within Apollo's post-estimation functions?
Hi Brenna apollo_prediction makes use of the full distribution of the random coefficients. So it will take the estimated parameters and create draws for the coefficients at the person level, using the number of draws you specified in the settings for draws. It will then calculate the probabilities w...
- 21 May 2020, 15:01
- Forum: Post-estimation analysis/use of results
- Topic: conditionals for random parameters when an individual has lots of observations
- Replies: 5
- Views: 7781
Re: conditionals for random parameters when an individual has lots of observations
Yes. that would make more sense
- 19 May 2020, 12:46
- Forum: Model specification
- Topic: Between subject design
- Replies: 3
- Views: 5876
Re: Between subject design
Dominik
I think what you need to do first is to analyse the choices in the two subsets. Your results are quite possibly driven by a situation where nobody in the private segment chooses option 6 or 8
Best wishes
Stephane
I think what you need to do first is to analyse the choices in the two subsets. Your results are quite possibly driven by a situation where nobody in the private segment chooses option 6 or 8
Best wishes
Stephane
- 18 May 2020, 14:12
- Forum: Errors during model validation and/or estimation.
- Topic: Error in Bayesian estimation
- Replies: 6
- Views: 9359
Re: Error in Bayesian estimation
Hi Jason this is a common issue that happens to people when using Bayesian estimation through RSGHB. The issue is that you ran the whole file in one go. RSGHB, which is used by Apollo for Bayesian estimation, asks you to confirm before continuing the estimation. As you ran the whole file in one go, ...
- 16 May 2020, 21:50
- Forum: Post-estimation analysis/use of results
- Topic: conditionals for random parameters when an individual has lots of observations
- Replies: 5
- Views: 7781
Re: conditionals for random parameters when an individual has lots of observations
Hi Wenjian so in effect you're treating each state as an "individual" in the model, with random heterogeneity across states. This is of course final methodologically, but you should be aware that with only 51 states, you only have a low number of "individuals" to which to fit a c...
- 15 May 2020, 16:09
- Forum: Examples (existing and requests for new ones)
- Topic: LC model with covariate
- Replies: 2
- Views: 9268
Re: LC model with covariate
Hi Suzana
this is the likelihood equivalent of Equation 11.5. I have clarified this in the manual for v.0.1.1. Please also consult Eqn 14 in https://www.caee.utexas.edu/prof/bhat/A ... egment.pdf
Best wishes
Stephane
this is the likelihood equivalent of Equation 11.5. I have clarified this in the manual for v.0.1.1. Please also consult Eqn 14 in https://www.caee.utexas.edu/prof/bhat/A ... egment.pdf
Best wishes
Stephane
- 15 May 2020, 14:29
- Forum: Post-estimation analysis/use of results
- Topic: conditionals for random parameters when an individual has lots of observations
- Replies: 5
- Views: 7781
Re: conditionals for random parameters when an individual has lots of observations
Hi Wenjian the error message you received was not very intuitive, apologies fort that. We have improved this error message in version 0.1.1. However, the computation of conditionals is not possible when using workInLogs. To compute conditionals, we need the probability of an individual's entire sequ...
- 14 May 2020, 20:30
- Forum: Model specification
- Topic: How to choose random parameters for MMNL model
- Replies: 3
- Views: 5945
Re: How to choose random parameters for MMNL model
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...