[Limdep Nlogit List] MNL: Quantities greater than one

Raimund Bau Raimund.Bau at rwth-aachen.de
Tue Jan 16 00:23:54 EST 2007


Dear Prof Greene, Prof Feinberg,

Thank you very much for your valuable answers to my question.

Maybe I will have to change my model and my entire approach. I thought 
that if a consumer chose the same product on two different occasions 
the overall fit of the MNL model would improve if the relative utility 
of that product was assigned a higher value compared to the purchase of 
one product of the same brand only. 
Now as far as I understand, you are saying that if the consumer 
exhibits the same behavior on a single occasion Nlogit/MNL would treat 
it as if the consumer bought just one item of that specific brand 
instead of treating it as if the consumer chose the brand twice. Thus 
the same consumer behavior would be treated differently if my first 
assumption is right.

Just to make sure we are discussing the same subject: I am not thinking 
of situations where a consumer chooses two different brands from the 
same category on a single occasion, which obviously would show a lack 
of consistency in terms of utility maximization within the bounds of 
such models. Furthermore, I am not really interested in quantities but 
rather brand choice and price sensitivity depending on advertising 
expenditures. Essentially my work is similar to Keane et al in 2004 who 
used a mixed MNL as well.

Thank you once again!

Raimund Bau
RWTH Aachen





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