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. We check the forum at least twice a week. It may thus take a couple of days for your post to appear and before we reply. There is no need to submit the post multiple times.

Search found 5 matches

by lemontree
30 Aug 2024, 16:13
Forum: Post-estimation analysis/use of results
Topic: MDCEV standard errors of elasticities
Replies: 1
Views: 22667

MDCEV standard errors of elasticities

Dear professor,

I have computed the price elasticities from a MDCEV model using the post estimation function and simulations.

I'm wondering how shall I get the standard errors for the price elasticities?
by lemontree
30 Nov 2023, 14:29
Forum: Errors during model validation and/or estimation.
Topic: error "undefined columns selected"
Replies: 2
Views: 14959

Re: error "undefined columns selected"

Many thanks, that solves the problem!
by lemontree
31 Oct 2023, 15:02
Forum: Errors during model validation and/or estimation.
Topic: error "undefined columns selected"
Replies: 2
Views: 14959

error "undefined columns selected"

Hi,

I have transformed the data for analyzing using the MDCEV model. I received the error Error in `[.data.frame`(database, , apollo_control$indivID) :
undefined columns selected .

Could you please help me to look at it?


# Set working directory
> setwd("..... ")
>
> # Initialise code ...
by lemontree
22 Jun 2023, 10:01
Forum: Model specification
Topic: Estimating MDCEV model with a price atrribute
Replies: 2
Views: 9099

Re: Estimating MDCEV model with a price atrribute

Oh that helps! Thank you very much!
by lemontree
21 Jun 2023, 15:43
Forum: Model specification
Topic: Estimating MDCEV model with a price atrribute
Replies: 2
Views: 9099

Estimating MDCEV model with a price atrribute

Dear developers,

I wanted to estimate MDCEV model with my SP data where each choices also have a price attribute.

I saw that in the Apollo manual, the sample data (time use data) for MDCEV does not include prices. As I understood, the base model of MDCEV assumes that there’s no price variation ...