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 190 matches
- 29 Aug 2023, 15:02
- Forum: Errors during model validation and/or estimation.
- Topic: errors in Latent class model
- Replies: 13
- Views: 30853
Re: errors in Latent class model
Hi Georgios, I'm not sure I fully understand all your questions, but will do my best to answer. I understand you are modelling a health-related choice using latent classes, and you have data from different countries. So the country is not the dependent variable. I am not sure what you mean by the &q...
- 27 Aug 2023, 13:08
- Forum: Model estimation
- Topic: How to change the setting of delta matrix (for complementarity)
- Replies: 7
- Views: 53605
Re: How to change the setting of delta matrix (for complementarity)
Hi, You can use the same trick for your situation, except that instead of using sociodemographics to determine the delta parameter to use in each case, you use the product category. So let's take your situation. You have 30 possible products (products 1 to 30), but in each observation a decision mak...
- 25 Aug 2023, 18:44
- Forum: Model estimation
- Topic: How to change the setting of delta matrix (for complementarity)
- Replies: 7
- Views: 53605
Re: How to change the setting of delta matrix (for complementarity)
Hi, The delta matrix can be defined with different values for each observation in your sample. Let's start with a situation with 3 alternatives, where everyone has the same complementarity/substitution (d) parameters. You would define the delta matrix as: delta <- matrix(c( 0, 0, 0, d21, 0, 0, d31, ...
- 25 Aug 2023, 18:27
- Forum: Errors during model validation and/or estimation.
- Topic: "Paramter does not influence the log-likelihood of your model" after included LV
- Replies: 12
- Views: 16719
Re: "Paramter does not influence the log-likelihood of your model" after included LV
Hi, The problem is that in your code you are overwriting some components of your utility, see lines 388-392 of your code below: P[["indic_savings"]] = apollo_firstRow(apollo_ol(ol_settings5, functionality), apollo_inputs ) P[["indic_prop"]] = apollo_firstRow(apollo_ol(ol_settings...
- 14 Aug 2023, 16:47
- Forum: Estimation results
- Topic: Error: Non-valid user-provided bgw_setting setting name detected: "writeIterMode"."
- Replies: 4
- Views: 6123
Re: Error: Non-valid user-provided bgw_setting setting name detected: "writeIterMode"."
Hi,
Please try updating the bgw package and running your model again. More specifically:
Best wishes
David
Please try updating the bgw package and running your model again. More specifically:
- Run the following line of code:
Code: Select all
install.packages("bgw")
- Then run your model again
Best wishes
David
- 10 Aug 2023, 15:27
- Forum: Model specification
- Topic: Logistic distribution of a random parameter
- Replies: 7
- Views: 10466
Re: Logistic distribution of a random parameter
Hi, Sorry for the very long delay in replying. It wasn't a simple question, so it kind of got put aside for a long while. I haven't gone through the whole Bahamonde-Birke & Ortúzar paper, but I did notice that you don't include an error term in LVC1 because you mention this is essentially the de...
- 10 Aug 2023, 14:17
- Forum: Data preparation, processing and pre-estimation analysis
- Topic: Non-overlapping choice sets
- Replies: 3
- Views: 14638
Re: Non-overlapping choice sets
Hi, Yes, you can do that without issues. That way of coding the alternative would be similar to how non-labelled data from an stated choice experiment is recorded. For example, le us imagine you are modelling ice cream choice. Ice-cream is described by both flavour and price. The flavours can be van...
- 14 Jul 2023, 19:22
- Forum: Model specification
- Topic: Introducing socio-demog and LVs in MMNL
- Replies: 2
- Views: 6349
Re: Introducing socio-demog and LVs in MMNL
Hi Anat, Unlike other software, Apollo provides the user with full freedom to define the utility functions. This increased freedom, however, also means that it is the user's responsibility to make sure the model is identifiable. Let's imagine you have a model with three alternatives: A, B, and C, ea...
- 26 May 2023, 17:15
- Forum: Model specification
- Topic: MNL model in WTP space and the ASC
- Replies: 5
- Views: 30897
Re: MNL model in WTP space and the ASC
Hi Margrethe, If you estimate a model in preference space and do not use additional scale parameters (as the ones used in the MNL_RP_SP example), then all your parameters will have the same scale, allowing you to compare among them. However, you have to keep in mind the scale of their associated exp...
- 26 May 2023, 16:56
- Forum: Estimation results
- Topic: Extremely large estimated standard deviation from a Mixed Logit model using a lognormal distribution
- Replies: 2
- Views: 4620
Re: Extremely large estimated standard deviation from a Mixed Logit model using a lognormal distribution
Hi Shan, Mixed logit models are much more complex than MNL models. As such, their identification is more complicated (see Walker (2002) for a detailed discussion), and there is no guarantee that your data will support a model with several random coefficients due to empirical identification issues (i...