[Limdep Nlogit List] Reference alternative of individual characteristics in the case of variable sized choice sets

[Lixian Qian]

Sorry for the format issue in the utility functions.

They should be as follows:

U(bus) = β_cost * cost(bus) + β_time *time (bus) + α_bus + γ_bus * income
U(train) = β_cost * cost(train) + β_time * time (train) + α_train + γ_train * income
U(car) =β_cost * cost(car) + β_time * time (car)



Best,
Lixian

-----Original Message-----
From: Limdep [mailto:limdep-bounces at mailman.sydney.edu.au] On Behalf Of Lixian Qian
Sent: 19 December 2018 22:44
To: limdep at limdep.itls.usyd.edu.au
Subject: [Limdep Nlogit List] Reference alternative of individual characteristics in the case of variable sized choice sets

Dear all,

I am running a discrete choice model with variable sized choice sets for two groups of people.
Say there are three alternatives, bus, train and car, where car is only available for some people. Each alternative has two attributes of cost and time, and each people has individual characteristic of income.

Then, I have following utility functions:

U(bus) = βcost costi,bus + βtime timei,bus + αbus + γbus incomei
U(train) = βcost costi,train + βtime timei,train + αtrain + γtrain incomei
U(car) =βcost costi,car + βtime timei,car

My puzzle is that for the people without car in their choice set, what is the reference alternative when estimating and interpreting the coefficients of income.

Appreciate your time to answer my question.
Thank you.


Best,
Lixian
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