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 2 matches
- 10 Jul 2023, 06:40
- Forum: Model estimation
- Topic: Mixed Logit with negative sigma?
- Replies: 3
- Views: 5139
Re: Mixed Logit with negative sigma?
Thank you Professor. I am not sure this is the best method to solve the problem or not but I tried to change the initial parameter setting to positive value and it gave a positive result.
- 05 Jul 2023, 02:56
- Forum: Model estimation
- Topic: Mixed Logit with negative sigma?
- Replies: 3
- Views: 5139
Mixed Logit with negative sigma?
I wonder why the estimates of sigma (standard deviation) from the Mixed Logit model are negative. An example is here. Estimates: Estimate s.e. t.rat.(0) Rob.s.e. Rob.t.rat.(0) mu_log_b_tt -1.9834 0.08812 -22.507 0.11479 -17.278 sigma_log_b_tt -0.4662 0.07753 -6.013 0.07436 -6.269 mu_log_b_tc -1.0246...