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 19 matches
- 13 May 2024, 11:39
- Forum: Model specification
- Topic: Start values for wta parameter
- Replies: 4
- Views: 2796
Re: Start values for wta parameter
Thank you Stephane. That's helped a lot!
- 22 Mar 2024, 10:24
- Forum: Post-estimation analysis/use of results
- Topic: Simulating WTP for normal dist. param when price is negative log normal/
- Replies: 1
- Views: 83
Simulating WTP for normal dist. param when price is negative log normal/
Hi, I estimated a MMNL which converged successfully. I am trying to simulate WTP for the ASC (ASC_low) which is normally distributed. My cost parameter is negatively log-normal distributed. this is the code: N <- 10000 b_low = rnorm(N, mean=model$estimate["asc_low_mu"], sd=model$estimate[&...
- 21 Mar 2024, 16:05
- Forum: Post-estimation analysis/use of results
- Topic: delta method to calculate WTP (normal and log-normal parameters)
- Replies: 10
- Views: 14672
Re: delta method to calculate WTP (normal and log-normal parameters)
Hello, Following David example for calculating WTP (normal and log normal params) in the following example N = 1000 b_attr = rnorm(N, mean=model$estimate["mu_attr"], sd=model$estimate["sg_attr"]) b_cost = -exp(rnorm(N, mean=model$estimate["mu_cost"], sd=model$estimate[&...
- 02 Mar 2024, 10:45
- Forum: Estimation results
- Topic: same code same data different "Number of modelled outcome"s
- Replies: 2
- Views: 489
Re: same code same data different "Number of modelled outcome"s
I think that understand the problem, the correct number of models is indeed 5061 = 723*7, I should have specified the "rows=(task==1)" for the LV estimation. I just don't understand how it converged in the previous version (0.2.9).
- 29 Feb 2024, 11:16
- Forum: Model specification
- Topic: Start values for wta parameter
- Replies: 4
- Views: 2796
Re: Start values for wta parameter
Sorry for not responding on time. Attached is the screenshot of a WTA menu.
- 26 Feb 2024, 22:26
- Forum: Estimation results
- Topic: same code same data different "Number of modelled outcome"s
- Replies: 2
- Views: 489
same code same data different "Number of modelled outcome"s
Hi all, I have estimated an MMNL model with one latent variable using Apollo 0.2.9 on R 4.3.1 I have 723 respondents answering 4 menus each with four alternatives (so the Number of modelled outcomes should be 11568) When I ran the model again using Apollo 0.3.1 on R 4.3.2, for some reason, the Numbe...
- 19 Feb 2024, 18:51
- Forum: Model specification
- Topic: Start values for wta parameter
- Replies: 4
- Views: 2796
Start values for wta parameter
Hi all, My data was generated from a DCE aimed at extracting WTA compensation for receiving a low-reliability electricity supply. To estimate the model in MNL, my initial thought was to force the WTA param. to be positive (i.e. by assigning log normal distribution). However, since optout was not an ...
- 07 Feb 2024, 12:51
- Forum: Model specification
- Topic: Are latent variables in Hybrid choice model correlated?
- Replies: 7
- Views: 6618
- 03 Feb 2024, 21:45
- Forum: Model specification
- Topic: Are latent variables in Hybrid choice model correlated?
- Replies: 7
- Views: 6618
Re: Are latent variables in Hybrid choice model correlated?
Please ignore the last part of the post "According to a reviewer (in transportation research part.. ), if this is the case, we should have an interaction term in the utility function that would allow an additional effect when both LVs. are high."
It is not relevant.. sorry for that.
It is not relevant.. sorry for that.
- 30 Jan 2024, 20:55
- Forum: Model specification
- Topic: Are latent variables in Hybrid choice model correlated?
- Replies: 7
- Views: 6618
Re: Are latent variables in Hybrid choice model correlated?
Sure, I put down the entire code (just in case..), the relevant part is in the random coefficient specification for the latent variables: NIR-skeptic and Norm . Short background: the model estimates the choice between leased ICE and hybrid vehicles accounting for concern of non-ionizing radiation (N...