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 17 matches
- 29 Feb 2024, 16:16
- Forum: Estimation results
- Topic: Unreasonable estimate for price and other attributes
- Replies: 7
- Views: 2614
Re: Unreasonable estimate for price and other attributes
Hi Prof. Stephane, I will provide further explanation here "You have 3 alternatives, but you are only estimating one constant. You can estimate J-1 constants, i.e. 2" If I understand correctly, I must estimate two asc, for example, alternative 1 and 3 as the following code: apollo_beta = c...
- 19 Feb 2024, 10:01
- Forum: Estimation results
- Topic: Unreasonable estimate for price and other attributes
- Replies: 7
- Views: 2614
Re: Unreasonable estimate for price and other attributes
Hi Prof. Stephane, I do not get the idea from your response. " first, you should always use a full set (i.e. J-1) alternative specific constants. " With this comment, does it mean that I need to assign, for example, asc of alternative 3 = 0? " But is your third alternative systematica...
- 03 Feb 2024, 01:58
- Forum: Estimation results
- Topic: Unreasonable estimate for price and other attributes
- Replies: 7
- Views: 2614
Re: Unreasonable estimate for price and other attributes
Hi Stephane, Thanks for your reply. In this choice experiment, I would like to test the effects of 5 attributes on consumer WTP of biscuits type of flour: wheat flour, BSG flour fibre information: no label, high fibre upcycled information: no label, upcycled logo texture description: no label, crisp...
- 27 Dec 2023, 11:40
- Forum: Estimation results
- Topic: Unreasonable estimate for price and other attributes
- Replies: 7
- Views: 2614
Unreasonable estimate for price and other attributes
Dear Professors, In my study, a choice experiment includes 5 attribtues: 4 binary attributes flour, fibre, upcycled, texture and price (4 levels: 25, 40, 55, 70). I have applied MNL as follows # clean rm(list = ls()); graphics.off() # .libPaths("C:/Rpack") library(openxlsx) library(apollo)...
- 06 Sep 2023, 12:30
- Forum: Errors during model validation and/or estimation.
- Topic: warning in MMNL
- Replies: 11
- Views: 8252
Re: warning in MMNL
Dear Prof. Hess,
Your explanation is in the page 2, then I did not see this.
Thanks for your explanation.
All the best,
Cuong
Your explanation is in the page 2, then I did not see this.
Thanks for your explanation.
All the best,
Cuong
- 24 Jul 2023, 19:34
- Forum: Errors during model validation and/or estimation.
- Topic: warning in MMNL
- Replies: 11
- Views: 8252
Re: warning in MMNL
Dear Prof. Hess, I have set the estimates from MNL model as the starting values apollo_beta=c(asc_alt3 = -1.99236, mu_b_ing_1 = -0.68717, sigma_b_ing_1 = 0, mu_b_ing_2 = -1.40654, sigma_b_ing_2 = 0, mu_b_fat = -0.19049, sigma_b_fat = 0, mu_b_carb = 0.22643, sigma_b_carb = 0, mu_log_b_price = -2.9301...
- 21 Jul 2023, 10:30
- Forum: Errors during model validation and/or estimation.
- Topic: warning in MMNL
- Replies: 11
- Views: 8252
Re: warning in MMNL
Dear Prof. Hess, Below are codes and estimates from MNL model of the same data. The codes # anal. Apollo ------------------------------------------------------------ ### Initialise code apollo_initialise() ### Set core controls apollo_control = list( modelName = "MNL_preference", modelDesc...
- 20 Jul 2023, 17:37
- Forum: Errors during model validation and/or estimation.
- Topic: warning in MMNL
- Replies: 11
- Views: 8252
Re: warning in MMNL
Hi, Below is the estimate results Preparing user-defined functions. Testing likelihood function... Overview of choices for MNL model component : alt1 alt2 alt3 Times available 22293.00 22293.00 22293.00 Times chosen 9174.00 8066.00 5053.00 Percentage chosen overall 41.15 36.18 22.67 Percentage chose...
- 20 Jul 2023, 11:00
- Forum: Errors during model validation and/or estimation.
- Topic: warning in MMNL
- Replies: 11
- Views: 8252
Re: warning in MMNL
Dear Prof. Hess, I have tried the same approach with the previous one, but different data . In this data, there are 4 binary non-price attributes (ing_1, ing_2, fat, carb) and continuous price attribute. I ran MNL that works well, but when I ran MMNL, the errors/warnings happen agian WARNING : Singu...
- 20 Jul 2023, 10:45
- Forum: Errors during model validation and/or estimation.
- Topic: warning in MMNL
- Replies: 11
- Views: 8252
Re: warning in MMNL
Dear Prof. Hess, I have changed the parameters of function apollo_randCoeff in which b_price is also randomed as shown in the following, and then it works apollo_randCoeff = function(apollo_beta, apollo_inputs){ randcoeff = list() randcoeff[["b_barn"]] = mu_b_barn + sigma_b_barn * draws_ba...