Business Functions Library for Excel

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Topic: Topic : How to generate S curve between a given beginning value and a given ending value
AuthorMessage
gfortuna
14 Feb 2012 12:26 am

I can't begin to understand the S curve function in the Business Functions Library.

But here's what I would greatly love to be able to do in Excel. Take a beginning value X at year 1 and an ending value Y at year 10 somehow specify which year I expect the S curve to begin to flatten, or at least indicate roughly where relative to the total period and then let some S curve function or formula fill in the data between the year 1 and year 10.

The purpose is to model a technology adoption curve such that the curve begins in year 1 at the specified level of X. There is steep growth in the first few years then a deceleration in growth that eventually peaks and levels out by year 10 at the specified value of Y The specific parameters of X, Y and YEAR AT WHICH GROWTH BEGINS TO FLATTEN are yet to be determined but that is what I am trying to do conceptually.

I am an ignoramus with respect to sophisticated math so anyone who feels willing to help would have to teaspoon feed it to me using these example parameters.

Thank You

johnd
14 Feb 2012 01:14 pm

SCurve calculates an S Curve.
You want to FIT an S Curve.
What are you showing varying by S Curve? The RATE of sales or the CUMULATIVE sales?
It makes a difference which one.
Scurve will not help you because it does not do a curve fit.
Functions that may help include FittedRate and CumCurve or perhaps PolyReg.
But I need to know if it's the rate that changes like an S Curve or the cumulative amount.

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