NBDdirichlet: plot.dirichlet – R documentation

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plot.dirichlet

Plot of theoretical penetration growth and buying rate growth

Description

This function plots a 'dirichlet' object. It is a method for the generic function plot for objects of the class 'dirichlet'. It plots the theoretical penetration growth and buying rate growth across multiple brands according to the Dirichlet model over a specified time sequence.

Usage

## S3 method for class 'dirichlet'
plot(x, t = 4, brand = 1:x$nbrand, incr = 1, result = NULL,...)

Arguments

`x`	An object of "dirichlet" class.
`t`	Maximum of the projection time period, which is specified as a multiple of the base time period. For example, if the base time period is quarterly, then `t=4` would mean annually.
`brand`	A vector specifying the subset of brands to be ploted.
`incr`	Increment for the time sequence that starts at 0. Its unit is one base time period. Can be a fractional number such as 0.1.
`result`	A list returned from the previous run of the `plot.dirichlet`. It is used to avoid repeating the computation when `incr` is changed.
`...`	Other parameters passing to the generic function.

Details

A time sequence will be made from 0 up to t with increment incr, against each component of which the theoretical penetration and brand buying rate will be plotted. Each plotted point represents the cumulated penetration or buying rate from time 0 to its current time point (expressed as the multiple of the base time period).

Value

A list with two components:

`pen`	A matrix with the penetration values. Its number of rows is the number of brands, and its number of columns is the length of the time sequence used for plotting the X coordinates of the points.
`buy`	A matrix with the buying rate values. Its dimension is the same as that of `pen`.

Author(s)

Feiming Chen

References

The Dirichlet: A Comprehensive Model of Buying Behavior. G.J. Goodhardt, A.S.C. Ehrenberg, C. Chatfield. Journal of the Royal Statistical Society. Series A (General), Vol. 147, No. 5 (1984), pp. 621-655

Examples

cat.pen <- 0.56 # Category Penetration
cat.buyrate <- 2.6 # Category Buyer's Average Purchase Rate in a given period.
brand.share <- c(0.25, 0.19, 0.1, 0.1, 0.09, 0.08, 0.03, 0.02) # Brands' Market Share
brand.pen.obs <- c(0.2,0.17,0.09,0.08,0.08,0.07,0.03,0.02) # Brand Penetration
brand.name <- c("Colgate DC", "Macleans","Close Up","Signal","ultrabrite",
"Gibbs SR","Boots Priv. Label","Sainsbury Priv. Lab.")

dobj <- dirichlet(cat.pen, cat.buyrate, brand.share, brand.pen.obs, brand.name)
plot(dobj)

NBDdirichlet

NBD-Dirichlet Model of Consumer Buying Behavior for Marketing Research

v1.3

GPL-3

Authors