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 2 matches

by twickr
02 Apr 2025, 10:39
Forum: Model specification
Topic: Defining the optout
Replies: 3
Views: 16316

Re: Defining the optout

Hi Stephane,

Thank you for your feedback. Yes, the base level was b_7times in the opt-out so, I'll keep that, or switch to effects coding.

Many thanks,
Tara
by twickr
19 Mar 2025, 12:12
Forum: Model specification
Topic: Defining the optout
Replies: 3
Views: 16316

Defining the optout

Hi Stephane and David,

I'm moving to Apollo after using STATA and am struggling with my most simple MNL model. I've noticed a discrepancy between the Apollo and STATA results, but only with the opt-out parameter. When I switch the reference level for my 'b_times' variable from 'b_7times' to 'b ...