[Limdep Nlogit List] Bass-type diffusion of innovation models

Erik Ferguson eferguson at aus.edu
Tue Sep 23 23:58:10 EST 2008


Upananda--

Since the '0' and '1' options represent infinity in terms of relative 
utility, tobit would work, assuming you have intermediate values between 
0 and 1 for partial adoption, but this is not particularly elegant from 
a mathematical perspective.

You could also define three (or more) 'choices' representing no adoption 
(F=0), full adoption (F=1), and partial adoption (0<F<1), and use an 
ordered probit or logit model to estimate the equation. If none of your 
values were 0 or 1, you could estimate choice probabilities directly a 
la Theil (1970).

Is your data for the degree of adoption at one moment in time, or do you 
have multiple data points? If you have time series data, you could 
estimate one of several Bass-type diffusion of innovation models.

I was wondering if LIMDEP can be used to estimate continuous Bass models 
using MLE procedures?

For the discrete Bass model, deltaAt = pm + (q-p)At-1 - q/mAt-1^2. I 
have estimated this model in LIMDEP by manually creating the three 
primary variables (Y,X1, X2), all of which are simple transformations of 
a single time series.

Is there a simple way to enter a set of say 85 independent time series 
variables, and estimate the Bass model without manually creating 3*85 
separate transformed variables?

Thanks!

Erik Ferguson
Master of Urban Planning Program
School of Architecture and Design
American University of Sharjah
PO Box 26666
Sharjah, UNITED ARAB EMIRATES
eferguson at aus.edu
971 6 515 2878 office
971 6 515 2800 fax
971 50 369 8355 mobile



Paragahawewa, Upananda wrote:
> Hi
> Could you please tell me whether Tobit model would applicable in the
> following case or some other options will better suit?
>  
> A given technology has been adopted fully by some individuals; to some
> extent by some individuals, and not at all by some. (example, a new
> clone of a crop grown in entire land area available in some case (1) ;
> part of the available land in some cases (0.7) and not at all (0) but
> still practice the old crop in some cases). Thanking you in advance
>  
>  
> Kind Regards
>  
> Upananda
>  
>  
>
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