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Search found 974 matches

by stephanehess
23 Feb 2024, 11:32
Forum: Estimation results
Topic: Unreasonable estimate for price and other attributes
Replies: 5
Views: 635

Re: Unreasonable estimate for price and other attributes

Hi Cuong You have 3 alternatives, but you are only estimating one constant. You can estimate J-1 constants, i.e. 2 My question was whether your third alternative in the survey is different from the other two, i.e. does it use different levels, etc? Regarding categorical, what I mean is that you dumm...
by stephanehess
23 Feb 2024, 11:26
Forum: Model specification
Topic: Start values for wta parameter
Replies: 1
Views: 151

Re: Start values for wta parameter

Anat

Can you provide us with a bit more detail, please, e.g. a screenshot of a SC task?

Thanks

Stephane
by stephanehess
23 Feb 2024, 11:22
Forum: Estimation results
Topic: MNL Model Estimation with covariate in WTP Space - Difficulty including covariate and to check correctness
Replies: 1
Views: 104

Re: MNL Model Estimation with covariate in WTP Space - Difficulty including covariate and to check correctness

Nico if you look at your partial derivatives of the utility functions, you will see that they are now different for the non price attributes given that you have placed the age interaction with cost on the parameter b_price_value so now you are introducing scale heterogeneity as a function of age. On...
by stephanehess
23 Feb 2024, 11:12
Forum: Post-estimation analysis/use of results
Topic: WTP distribution in preference space
Replies: 1
Views: 164

Re: WTP distribution in preference space

Hi

Yes, a ratio of two lognormals is a lognormals, and if one (and only one) of the two is a negative lognormal, then the ratio is negative lognormal too

Re your plots, are you using a low number of draws? Maybe also try without imposing the limits

Stephane
by stephanehess
23 Feb 2024, 11:08
Forum: Model specification
Topic: ICLV model specification in unlabelled form
Replies: 6
Views: 6018

Re: ICLV model specification in unlabelled form

Hi

In order for us to help you, you need to show us the output, i.e. the parameter estimates.

Can you please also confirm that a MNL and mixed logit model worked on the data before moving to hybrid choice?

Thanks
by stephanehess
06 Feb 2024, 19:56
Forum: Estimation results
Topic: Unreasonable estimate for price and other attributes
Replies: 5
Views: 635

Re: Unreasonable estimate for price and other attributes

Hi

first, you should always use a full set (i.e. J-1) alternative specific constants.

But is your third alternative systematically different from the other two which could lead to the issues you're seeing

Stephane
by stephanehess
03 Feb 2024, 14:05
Forum: Model estimation
Topic: Estimation of MNL and MMNL in WTP space issues
Replies: 5
Views: 775

Re: Estimation of MNL and MMNL in WTP space issues

Hi

I also need to know the LL you get with MNL and in WTP space, please, i.e. where it runs out of iterations

Stephane
by stephanehess
01 Feb 2024, 11:15
Forum: Model estimation
Topic: Estimation of MNL and MMNL in WTP space issues
Replies: 5
Views: 775

Re: Estimation of MNL and MMNL in WTP space issues

Hi

did you first try a model in preference space?

Stephane
by stephanehess
31 Jan 2024, 10:51
Forum: Estimation results
Topic: Interpretation of coefficients
Replies: 3
Views: 497

Re: Interpretation of coefficients

1. Again, it depends on the units. Imagine that I have b_cost = -0.1 and b_time = -0.05. You can't say that cost matters more than time as it depends on the units. Imagine that cost is in € and time is in minutes. Then what the above is telling us is that €1 is more important than 1 minute, but obvi...
by stephanehess
30 Jan 2024, 16:00
Forum: Model specification
Topic: Nested Logit-location choice joint with mode utility
Replies: 1
Views: 610

Re: Nested Logit-location choice joint with mode utility

Hi

I think the reason your model is not working at the moment is that you only have constants in the utilities, which makes it impossible to estimate a nesting structure

Regarding your second question, can you explain a bit more what you mean, please?

Thanks