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 1042 matches
- 06 May 2024, 08:19
- Forum: Model specification
- Topic: ICLV model specification in unlabelled form
- Replies: 8
- Views: 7741
Re: ICLV model specification in unlabelled form
Hi many apologies for the slow reply, your messages had been lost. First, "relative function convergence" is the BGW terminology for convergence, so that's fine. Second, in relation to your ASCs, you have: b_ASC*(asc_alt1==0) + b_ASC*(asc_alt1==1) which would mean the ASC is used for both ...
- 06 May 2024, 08:13
- Forum: Model specification
- Topic: adding context variables in class allocation model in latent class logit model
- Replies: 4
- Views: 1823
Re: adding context variables in class allocation model in latent class logit model
Hi
apologies for the slow reply
Your problem is caused by the effects coding you have implemented in the data. If you have only three levels, then you should also only estimated two parameters, not three. But I would suggest you just use dummy coding
Stephane
apologies for the slow reply
Your problem is caused by the effects coding you have implemented in the data. If you have only three levels, then you should also only estimated two parameters, not three. But I would suggest you just use dummy coding
Stephane
- 06 May 2024, 08:08
- Forum: Post-estimation analysis/use of results
- Topic: Elasticity analysis for unlabeled alternatives
- Replies: 1
- Views: 76
Re: Elasticity analysis for unlabeled alternatives
Hi many apologies for the slow reply, we had missed your post In relation to your questions: 1. Is classical elasticity analysis suitable for unlabeled cases? (While computations may be possible, I am interested in ascertaining the theoretical relevance of confirming sensitivity to specific attribut...
- 06 May 2024, 08:03
- Forum: Post-estimation analysis/use of results
- Topic: Out of sample results
- Replies: 3
- Views: 1774
Re: Out of sample results
Hi apologies for the slow reply So what you're finding is that you MMNL overfits the estimation data a bit more than MNL, but these differences are small. No, Apollo does not compute the % correct predicted metric as this is a misleading metric that is contrary to probabilistic choice models. It sho...
- 06 May 2024, 07:57
- Forum: Estimation results
- Topic: Unreasonable estimate for price and other attributes
- Replies: 7
- Views: 2703
Re: Unreasonable estimate for price and other attributes
Hi
apologies for the slow reply. Yes, correct on question 1, and no need to dummy code for price.
This could just be a case that your data gives unreasonable results, I can't see anything wrong with the model per se
Stephane
apologies for the slow reply. Yes, correct on question 1, and no need to dummy code for price.
This could just be a case that your data gives unreasonable results, I can't see anything wrong with the model per se
Stephane
- 06 May 2024, 07:55
- Forum: Errors during model validation and/or estimation.
- Topic: Error in estimating Latent class model with RP-SP data
- Replies: 9
- Views: 220
Re: Error in estimating Latent class model with RP-SP data
You'll need to be a bit careful here as combineModels is used inside the LC. probably best to work with temporary lists rather than P for RP and SP. You also need to tell it which ones to combine Something like this (look where I have used P_temp and where I have used P You probably need to make som...
- 06 May 2024, 07:47
- Forum: Errors during model validation and/or estimation.
- Topic: Error while estimating a Hybrid latent class choice model
- Replies: 3
- Views: 90
Re: Error while estimating a Hybrid latent class choice model
Hi
yes, please send me the data and code outside the forum and I'll have a look
Stephane
yes, please send me the data and code outside the forum and I'll have a look
Stephane
- 06 May 2024, 07:46
- Forum: Estimation results
- Topic: Positive price coefficient in RPL model estimation
- Replies: 10
- Views: 340
Re: Positive price coefficient in RPL model estimation
David to get standard errors, you would likely need to do sampling from the asymptotic parameter distribution. We've not implemented any code for that. But with lognormals, you can also calculate the moments for the ratio analytically (a ratio of two lognormals is a lognormal) and then you can use t...
- 05 May 2024, 18:39
- Forum: Post-estimation analysis/use of results
- Topic: WTP distribution in preference space
- Replies: 3
- Views: 2191
Re: WTP distribution in preference space
Hi
apologies for the slow reply. What you're seeing is caused by using limits in plotting. You're computing the overall density, but then you're plotting it for only a small part of the overall domain, and that's reflected in the shape you're seeing
Stephane
apologies for the slow reply. What you're seeing is caused by using limits in plotting. You're computing the overall density, but then you're plotting it for only a small part of the overall domain, and that's reflected in the shape you're seeing
Stephane
- 05 May 2024, 12:10
- Forum: Model specification
- Topic: Include independent variables with missing values
- Replies: 4
- Views: 2467
Re: Include independent variables with missing values
Hi
in that case, you would have missing data for a dependent variable (indicator in hybrid choice), and you would skip those rows for that dependent variable only. See the 'rows' setting
Stephane
in that case, you would have missing data for a dependent variable (indicator in hybrid choice), and you would skip those rows for that dependent variable only. See the 'rows' setting
Stephane