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 16 matches

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by manes
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: 13792

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[&...
by manes
02 Mar 2024, 10:45
Forum: Estimation results
Topic: same code same data different "Number of modelled outcome"s
Replies: 2
Views: 138

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).
by manes
26 Feb 2024, 22:26
Forum: Estimation results
Topic: same code same data different "Number of modelled outcome"s
Replies: 2
Views: 138

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...
by manes
19 Feb 2024, 18:51
Forum: Model specification
Topic: Start values for wta parameter
Replies: 1
Views: 2407

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 ...
by manes
07 Feb 2024, 12:51
Forum: Model specification
Topic: Are latent variables in Hybrid choice model correlated?
Replies: 7
Views: 6242

Re: Are latent variables in Hybrid choice model correlated?

Thanks a lot!
by manes
03 Feb 2024, 21:45
Forum: Model specification
Topic: Are latent variables in Hybrid choice model correlated?
Replies: 7
Views: 6242

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.
by manes
30 Jan 2024, 20:55
Forum: Model specification
Topic: Are latent variables in Hybrid choice model correlated?
Replies: 7
Views: 6242

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...
by manes
29 Jan 2024, 21:56
Forum: Model specification
Topic: Are latent variables in Hybrid choice model correlated?
Replies: 7
Views: 6242

Re: Are latent variables in Hybrid choice model correlated?

Hello, I have estimated HCM with two latent variables (LV1 and LV2) both are assumed as random vars. There is a reason to believe that they are positively correlated. To test this assumption I specified the following: apollo_draws = list( ... interNormDraws = c("eta1","eta2"), .....
by manes
13 Oct 2023, 16:45
Forum: Other
Topic: Reporting results of CFA in HCM
Replies: 2
Views: 15257

Re: Reporting results of CFA in HCM

Thanks!
by manes
12 Oct 2023, 18:06
Forum: Other
Topic: Reporting results of CFA in HCM
Replies: 2
Views: 15257

Reporting results of CFA in HCM

Dear all, I have run a Hybrid Choice Model with a latent attitude. I have used items from a validated attitudinal scale (using Ordered logit estimation for the latent var). Only 4 out of 6 items are included in the HCM (with all 4 thresholds for each item are significant). Do I need to report the re...

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