Re: Information about S-curve in SPSS

Posted by Edgar F. Johns on Feb 09, 2007; 12:32am
URL: http://spssx-discussion.165.s1.nabble.com/Information-about-S-curve-in-SPSS-tp1073784p1073785.html

Take a look at the econometrics literature. The s-curve is also known as the
logistic model or function. A classic example is adoption rate of a new
product/technology. Initially, the adoption rate is slow until some critical
mass is reached. Then adoption is fast until it reaches saturation.

The classic econometrics text is Greene, W. H. (2000). Econometric analysis.
(4th Ed.). Upper Saddle River, NJ: Prentice-Hall.

Edgar
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-----Original Message-----
From: SPSSX(r) Discussion [mailto:[hidden email]] On Behalf Of
Sungeun Chung
Sent: Thursday, February 08, 2007 5:14 PM
To: [hidden email]
Subject: Information about S-curve in SPSS

SPSS expert,

I used "Curve Estimation" to find a functional form for my data.  I found
that S-curve is best fitted.

I found the equation for S-curve in the help menu:

 S-curve. Model whose equation is Y = e**(b0 + (b1/t)) or ln(Y) = b0 +
(b1/t).

I need more information about this function.  Can anyone give me references
about the above equation?

Thanks in advance,

--
Sungeun Chung, Ph.D.

Assistant Professor
Department of Communication
Memorial Hall 303G
Western Illinois University
Macomb, IL 61455-1390
Tel. [phone]
E-mail: [hidden email]; [hidden email]