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Search found 14 matches

by DamienJ
05 Jun 2024, 10:41
Forum: Model specification
Topic: WTP-space correlation between normals and log-normals
Replies: 4
Views: 12040

Re: WTP-space correlation between normals and log-normals

Thank you for the advices. We will try the log-uniform;

Damien
by DamienJ
04 Jun 2024, 13:29
Forum: Model specification
Topic: WTP-space correlation between normals and log-normals
Replies: 4
Views: 12040

Re: WTP-space correlation between normals and log-normals

Thank you for you message and the precisions.

Actually, we wanted the price attribute to be positive (price is a subsidy), so it makes senses to use log-normal.

I ran a model with the previously given code, and I get the following results (see below):

This "looks" satisfactory, but I have two ...
by DamienJ
03 Jun 2024, 14:03
Forum: Model specification
Topic: WTP-space correlation between normals and log-normals
Replies: 4
Views: 12040

WTP-space correlation between normals and log-normals

We are trying to estimate a model in the WTA space. (price is a subsidy). To do that, we are making the hypothesis that the price (subsidy) paramater is distributed as a log-normal, and that the other parameters are normally distributed and correlated (including with the price parameter) and can ...
by DamienJ
17 Jan 2024, 12:10
Forum: Errors during model validation and/or estimation.
Topic: Unconditionals
Replies: 13
Views: 227173

Re: Unconditionals

I am not sure a generic solution was found for this problem?
I have the same kind of message (also for a LC-MXL ANA type of model). I can also share my data and model if needed
by DamienJ
15 Dec 2023, 15:18
Forum: Model specification
Topic: probabilities of classes vary across choice tasks in a LC-MXL model
Replies: 1
Views: 5608

probabilities of classes vary across choice tasks in a LC-MXL model

I am trying to develop a model testing for ANA (using a LC-Mixed Logit model) to avoid inflating the ANA.
Given the high number of possible classes, I am using the methodology proposed by Hole, 2011. This gave me plausible results.
From this model, I wanted to test the idea that attendance might ...
by DamienJ
16 Jun 2023, 19:51
Forum: Model specification
Topic: Log-uniform distribution (always positive)
Replies: 4
Views: 10946

Re: Log-uniform distribution (always positive)

Indeed, I haven't put enough thought on this, as this will make the distribution start at at 1
Thank you.
by DamienJ
16 Jun 2023, 06:23
Forum: Model specification
Topic: Log-uniform distribution (always positive)
Replies: 4
Views: 10946

Re: Log-uniform distribution (always positive)

Thank you for the clarification about the correlation. For the offset, I assumed that it was equal to zero, but I guess it is better to verify this!

Damien
by DamienJ
09 Jun 2023, 13:08
Forum: Model specification
Topic: Log-uniform distribution (always positive)
Replies: 4
Views: 10946

Log-uniform distribution (always positive)

In a WTP-space mixed logit model, I want to test a log-uniform distribution for the price attribute '(rationale: always positive and avoid long tail of log-normal);

I have two questions (related code below)

1. Is the specification "exp(b_lambda * draws_lambda)" correct if I want a log-uniform ...
by DamienJ
26 Apr 2023, 06:28
Forum: Model specification
Topic: Availability of alternatives different for each class in a LC model
Replies: 4
Views: 9988

Re: Availability of alternatives different for each class in a LC model

It now runs well including using multithreading. Thank you. Damien
by DamienJ
25 Apr 2023, 14:28
Forum: Model specification
Topic: Availability of alternatives different for each class in a LC model
Replies: 4
Views: 9988

Re: Availability of alternatives different for each class in a LC model

Dear Prof Hess,
Just sent a sample data set on your gmail address and contact@apollochoicemodelling.com I hope this will reach you. Thank you.
Damien