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 6 matches
- 23 Apr 2024, 11:47
- Forum: Estimation results
- Topic: Missing model-fit parameters
- Replies: 3
- Views: 205
Re: Missing model-fit parameters
Hi Stephane, Thanks for the reply. I updated to 0.3.1, the same problem occurs. Here is the formatted output, using same data and code as before: Preparing user-defined functions. Testing likelihood function... Overview of choices for MNL model component Best_Class_1: alt1B alt2B alt3B alt4B Times a...
- 26 Mar 2024, 10:32
- Forum: Estimation results
- Topic: Missing model-fit parameters
- Replies: 3
- Views: 205
Missing model-fit parameters
Hi, I've specified a Latent Class model for BWS Case 1 (no covariates). The model converges but is missing the Rho-sq parameters and the BIC. I'm using Apollo 0.2.9 See below for data structure, code and output: Best wishes, Jay Data structure: glimpse(database) Rows: 7,408 Columns: 77 $ uuid <chr> ...
- 12 Jun 2023, 12:15
- Forum: Model specification
- Topic: Position-specific constants for best vs worst choices
- Replies: 7
- Views: 4314
Re: Position-specific constants for best vs worst choices
Thanks Stephane, I specified it as below - could you check if that's ok please? Another question I have is I recorded the choice order between best and worst choices - is it possible to specify the model to handle observed choice rather than making an assumption (i.e. EL with best then worst or MaxD...
- 05 May 2023, 22:17
- Forum: Model specification
- Topic: Position-specific constants for best vs worst choices
- Replies: 7
- Views: 4314
Re: Position-specific constants for best vs worst choices
Yes, there's four alternatives for each choice set (16 items in total and 8 choice sets). If I assume a sequential model (respondents choose best item first, then worst item) and want ASCs for best and worst choices separately, then there should be 4 position-specific constants for the best choice a...
- 11 Apr 2023, 12:47
- Forum: Model specification
- Topic: Position-specific constants for best vs worst choices
- Replies: 7
- Views: 4314
Re: Position-specific constants for best vs worst choices
**EDIT: I've solved this by creating a new set of dummy variables for each attribute and position, and recoding the worst choice variable. I then used these new variables to define class specific utilities for the worst choices, and set the `alternatives` argument of mnl_settings to have only 3 alte...
- 31 Jan 2023, 16:43
- Forum: Model specification
- Topic: Position-specific constants for best vs worst choices
- Replies: 7
- Views: 4314
Position-specific constants for best vs worst choices
Hi! I have specified a sequential BW LC (no covariates). It is a case 1 BW with 16 items in total, 8 choice-sets and 4 items per choice set. In the results, there is a non-sig trend for a lower value estimate of the position-specific constant across alternatives (i.e. a hint of position bias!). I'd ...