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 11 matches

by caldeiraga
09 Mar 2023, 15:26
Forum: Errors during model validation and/or estimation.
Topic: Error when using mixed logit with only one observation per individual
Replies: 6
Views: 2718

Re: Error when using mixed logit with only one observation per individual

Hi Stephane and David, I'm trying to estimate a mixed ordered choice model with random threshold parameters. Bellow is the code I'm using to estimate the model. I got the following message: "Error in apollo_validate(op_settings, modelType, functionality, apollo_inputs) : Tresholds for model com...
by caldeiraga
08 Oct 2021, 11:35
Forum: Post-estimation analysis/use of results
Topic: Delta method for RRM models
Replies: 3
Views: 3814

Re: Delta method for RRM models

Hi Prof Stephane Thanks for the answer. I'm using as reference the Chorus (2012) https://www.tandfonline.com/doi/abs/10.1080/01441647.2011.609947 and Dekker (2014) https://www.sciencedirect.com/science/article/abs/pii/S1755534514000360?via%3Dihub papers. I'm aware of the differences between the RUM ...
by caldeiraga
07 Oct 2021, 20:39
Forum: Post-estimation analysis/use of results
Topic: Delta method for RRM models
Replies: 3
Views: 3814

Delta method for RRM models

Hi David and Stephane, I have a question about the VTT error calculated from a RRM model. If I understood correctly the paper of Daly et al. (2012) about the computation of this measure, we calculate errors from a transformation of the parameters, and in the case of VTT is the ratio of the derivativ...
by caldeiraga
09 Jul 2021, 21:54
Forum: Model specification
Topic: ordinal logit using second-order measurement component
Replies: 6
Views: 7886

Re: ordinal logit using second-order measurement component

I found the error prof Hess, I was specifying in a wrong way the SEX variable and now it works. Thanks!

Best,
Gabriel
by caldeiraga
08 Jul 2021, 19:36
Forum: Model specification
Topic: ordinal logit using second-order measurement component
Replies: 6
Views: 7886

Re: ordinal logit using second-order measurement component

My model has an ordered variable with 4 outcomes, I just put two variables to test with it works, but then I get the following message: Error in apollo_validate(ol_settings, modelType, functionality, apollo_inputs) : Some values inside V are not finite for model component "model" Além diss...
by caldeiraga
08 Jul 2021, 02:48
Forum: Model specification
Topic: ordinal logit using second-order measurement component
Replies: 6
Views: 7886

Re: ordinal logit using second-order measurement component

Hi prof Hess, I think it's a silly question, but, if I want to specify an ordered model like in the polr function from the MASS package, where I specify the utility (in the Manual says V is a numeric vector) in the model? All the examples in the manual and the topics here discuss the specification o...
by caldeiraga
08 Jun 2021, 18:57
Forum: Post-estimation analysis/use of results
Topic: Willingness-to-pay considering binary variable
Replies: 5
Views: 6894

Re: Willingness-to-pay considering binary variable

Hi David, I have a question about computing Average Marginal effect for dummy variables, when you write P(i | x1=1) - P(i | x1=0), does it mean that I need to compute the probability for the complete estimated sample, and then subselect in the sample the observations with x1=1 and x1=0 and calculate...
by caldeiraga
29 Sep 2020, 02:42
Forum: Examples (existing and requests for new ones)
Topic: Triangular and Johnson's Sb distribution
Replies: 4
Views: 9579

Re: Triangular and Johnson's Sb distribution

Thanks prof Hess!

Best regards,

Gabriel
by caldeiraga
24 Sep 2020, 15:55
Forum: Examples (existing and requests for new ones)
Topic: Triangular and Johnson's Sb distribution
Replies: 4
Views: 9579

Re: Triangular and Johnson's Sb distribution

Hi, Following the code I used for the Sb (it worked, but my question is about the support parameters) and the symmetrical triangular distribution ### Set parameters for generating draws apollo_draws = list( interDrawsType = 'halton', interNDraws = 200, interNormDraws = c("draws_tt"), inter...
by caldeiraga
14 Sep 2020, 22:54
Forum: Examples (existing and requests for new ones)
Topic: Triangular and Johnson's Sb distribution
Replies: 4
Views: 9579

Triangular and Johnson's Sb distribution

Hi, I'm estimating a MMNL model and testing some distributions like Normal, Log-Normal, Johnson's Sb, etc. I tested a triangular distribution based on this paper https://www.jstatsoft.org/article/view/v074i10 but it didn't work. Can anyone give an example of this distribution in Apollo? In the case ...