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by Ariana_1987
02 Feb 2022, 02:36
Forum: Models and estimation
Topic: including socioeconomic variables in the utility functions
Replies: 2
Views: 4942

Re: including socioeconomic variables in the utility functions

Hi Stephane,

Thank you so much for the clarification. I really appreciate your help!

Best,
Ariana
by Ariana_1987
31 Jan 2022, 04:00
Forum: Models and estimation
Topic: including socioeconomic variables in the utility functions
Replies: 2
Views: 4942

including socioeconomic variables in the utility functions

Hello, In my dataset, I have many socioeconomic variables such as age_group, Disability, Income_group. I have 4 mode choices including Drive, Ride, Bus, Walk. When I put all the socioeconomic variables in each of the utility functions, it leads to over-specification of variables. What is the solutio...
by Ariana_1987
17 Dec 2021, 17:32
Forum: Estimation results
Topic: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients
Replies: 11
Views: 8535

Re: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients

Stephane,

I got it! Thanks a lot for your help!
by Ariana_1987
09 Dec 2021, 16:54
Forum: Models and estimation
Topic: defining a base category
Replies: 1
Views: 4794

defining a base category

Hello, I have a basic question about defining utility functions in Apollo. When we want to fit a multinomial logit regression, should we consider one of the alternatives as a base category like this? V[["A"]]= b_cov*cov_A + b_acc1*acc1_A + b_acc2*acc2_A + b_bid * bid_A V[["B"]]= ...
by Ariana_1987
09 Dec 2021, 15:53
Forum: Estimation results
Topic: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients
Replies: 11
Views: 8535

Re: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients

Stephane,

Sorry for my late response. Yes. I also tried that and still the bus cost coefficient has a positive sign.
by Ariana_1987
03 Dec 2021, 01:02
Forum: Estimation results
Topic: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients
Replies: 11
Views: 8535

Re: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients

Thanks, yes, here is the results: Estimates: Estimate s.e. t.rat.(0) Rob.s.e. Rob.t.rat.(0) A_drive_time -0.27983 0.11261 -2.4850 0.09830 -2.8468 B_ride_time -0.19440 0.10766 -1.8057 0.09960 -1.9518 A_Car 0.18109 0.80249 0.2257 0.77829 0.2327 A_driving_Freq 2.10043 0.46973 4.4716 0.46995 4.4695 C_wa...
by Ariana_1987
02 Dec 2021, 16:51
Forum: Estimation results
Topic: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients
Replies: 11
Views: 8535

Re: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients

Hi Stephane,

Thanks. I have attached the table as an image file:

Best,
Ariana
by Ariana_1987
29 Nov 2021, 15:29
Forum: Estimation results
Topic: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients
Replies: 11
Views: 8535

Re: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients

Hi Stephane, Here is the pivot table of the bus_cost column: Row Labels Count of bus_cost 0 21 1 23 1.1 103 1.5 3 2.2 1 3.35 1 4.5 1 (blank) Grand Total 153 For 21 people, the price is zero, because the bus option is not available for them. Thanks! Ariana
by Ariana_1987
29 Nov 2021, 02:37
Forum: Estimation results
Topic: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients
Replies: 11
Views: 8535

Re: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients

Hi Stephane, Thank you so much for your helpful answer! Regarding the second one, 20 out of 153 individuals chose bus as their mode choice. While bus_time varied among these individuals, the price for all the 20 individuals was the same. Is this the reason that I get this unexpected sign? Best, Ariana
by Ariana_1987
28 Nov 2021, 02:54
Forum: Estimation results
Topic: In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients
Replies: 11
Views: 8535

In multinomial logit regression; NaNs produced, an unexpected sign of one of the coefficients

Hello, I wanted to do a multinomial logit model for travel mode choice on my dataset. 1- When I want to estimate alternate specific constants, the results are strange and the errors are too big. 2-Also, the sign of the beta parameter for the "bus_cost" variable is positive. But a positive ...

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