Important: Read this before posting to this forum

  1. 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.
  2. 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
  3. Before asking a question on the forum, users are kindly requested to follow these steps:
    1. Check that the same issue has not already been addressed in the forum - there is a search tool.
    2. 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
    3. Check the frequently asked questions section on the Apollo website, which discusses some common issues/failures. Please see http://www.apollochoicemodelling.com/faq.html
    4. Make sure that R is using the latest official release of Apollo.
  4. If the above steps do not resolve the issue, then users should follow these steps when posting a question:
    1. provide full details on the issue, including the entire code and output, including any error messages
    2. 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 1066 matches

by stephanehess
27 May 2024, 14:32
Forum: Model estimation
Topic: Function evaluation limit exceeded.
Replies: 7
Views: 236

Re: Function evaluation limit exceeded.

Your estimate for sig is very suspicious. What did you get with the non-random version?
by stephanehess
27 May 2024, 08:33
Forum: Errors during model validation and/or estimation.
Topic: Error in the model command when using EM algorithms
Replies: 1
Views: 15

Re: Error in the model command when using EM algorithms

Hi

thanks for spotting this issue. This has been fixed in the development version (0.3.3) which you can download from http://apollochoicemodelling.com/code.html

Best wishes

Stephane
by stephanehess
24 May 2024, 15:51
Forum: Model estimation
Topic: Posterior probability more than 100%?
Replies: 4
Views: 2113

Re: Posterior probability more than 100%?

Hi this was an old bug that affected cases where the IDs in the data were not sorted. Of course, that shouldn't matter, and we have fixed it in the new development version that you can download from http://apollochoicemodelling.com/code.html Alternatively, if you want to wait for the next CRAN relea...
by stephanehess
23 May 2024, 18:12
Forum: Post-estimation analysis/use of results
Topic: post-estimation scenario analysis
Replies: 12
Views: 10114

Re: post-estimation scenario analysis

Hi

there is a choice model in each class. When you change an attribute, the prediction changes in each class, and of course then also in the overall model, which is a weighted average across the classes.

Stephane
by stephanehess
23 May 2024, 18:08
Forum: Errors during model validation and/or estimation.
Topic: Error in MNL estimation
Replies: 5
Views: 193

Re: Error in MNL estimation

I now had a closer look and you are using the same attribute names in the utilities for alternatives 1 and 2. This, alongside the constants, makes it impossible for you to estimate the model. There should be separate attributes in the utilities for different alternatives, as only differences in util...
by stephanehess
23 May 2024, 07:16
Forum: Errors during model validation and/or estimation.
Topic: Error in MNL estimation
Replies: 5
Views: 193

Re: Error in MNL estimation

It's clearly overspecified then. Can you share your data and code with me outside the forum and I'll have a look?
by stephanehess
23 May 2024, 07:14
Forum: Post-estimation analysis/use of results
Topic: post-estimation scenario analysis
Replies: 12
Views: 10114

Re: post-estimation scenario analysis

Alvin the answers to the first two are in the manual. You can use apollo_unconditionals for both of these. Regarding the third, purchase price is an attribute of the alternatives and thus included in the within class choice model, not the class allocation model, so it will not lead to such a shift S...
by stephanehess
22 May 2024, 12:12
Forum: Model specification
Topic: Hybrid_LC_with_OL_example_data
Replies: 1
Views: 81

Re: Hybrid_LC_with_OL_example_data

Hi

apologies for the slow reply. We believe we have fixed this issue in the latest development version - can you try it by downloading from http://apollochoicemodelling.com/code.html

Thanks

Stephane & David
by stephanehess
22 May 2024, 12:09
Forum: Errors during model validation and/or estimation.
Topic: Error (pi * p : non-conformable arrays) while estimating Hybrid LC with OL
Replies: 1
Views: 56

Re: Error (pi * p : non-conformable arrays) while estimating Hybrid LC with OL

Hi

apologies for the slow reply. We believe we have fixed this issue in the latest development version - can you try it by downloading from http://apollochoicemodelling.com/code.html

Thanks

Stephane & David
by stephanehess
22 May 2024, 11:53
Forum: Model specification
Topic: Joint Estimation for Dual Response Survey with Two Segments
Replies: 3
Views: 164

Re: Joint Estimation for Dual Response Survey with Two Segments

Hi

the two separate models is the same as if you had a fully segmented model. So you can use a LR test to compare the sum of the two separaet models against your generic model without differences. The degrees of freedom would be the additional parameters needed for two separate models

Stephane