Hi:

Are you perhaps thinking of conjoint analysis?

Dennis

On Wed, Jan 5, 2011 at 1:30 AM, Graham Smith <myotistwo@gmail.com> wrote:

> Ben
>
>
> >   Perhaps you can specify your question more precisely, or differently.
> > The way I interpret it, if there are no interactions in price
> > (e.g. you get a discount for buying more than one book at a time)
> > or in value (e.g. you learn more from one book having read another),
> > then you get the best value/price ratio by taking only the book with
> > the highest value/price.  (If you take no books at all, your value/price
> > ratio is undefined.)  The algebra below shows that combining a lower
> > value/price book with a higher one always lowers your overall value/price
> > ratio.
> >
>
> Thanks, for the pointers on R functions. My question was as superficial as
> it sounded. I have a commercial programme that does this (one of several
> that are available), and wondered if there was an R package that provided
> the same tools. It's a common tool, and I had hoped to have explained
> enough
> to allow an appropriate package to be identified, so I could have a quick
> look at what it does.
>
> But having started this, I now feel obliged to clarify the question. I only
> chose books as an easy example, you could substitute alternative marketing
> strategies, monitoring programmes, choice of ornaments for a new house, or
> holidays etc. So there could be only a few potential combinations or
> hundreds.
>
> But to stick with the books, and only three options: A, B and C
>
> Book A costs $100 and I have given it a subjective value of  50
> Book B costs  $36  and I have given it a subjective value of  60
> Book C costs  $50 and I have given it a subjective value of 80
>
> So book A is costing me $2 per value unit, Book B $0.6 per value unit and
> book C Ł0.63 per value unit.
>
> Buying books A+B gives me a $1.24 per value unit
> Buying books A+C gives $1.07 per value unit
> Buying books B+C gives 0.61 per value unit
> Buying books A+B+C gives 0.97 per value unit
>
> So in terms of value for money, there are three contenders
>
> Book B on its own, Book C on its own, or buying both books B and C.
>
> Book B $36.00 and value 60
> Book C $50.00 and value 80
> Book B+C  at $76.00 and value 140
>
> Depending on how you are using this tool, you can either use it to decide
> how spend an existing budget, or use it to set a budget.
>
> Seems hardly worth the bother for three books but if you are looking at 20
> books or 30 different monitoring options etc, it gives a useful insight
> into
> how best to spend or set a budget
>
> The commercial software graphs this costs vs values so you usually end up
> with some sort of an asymptotic graph where you can see that spending below
> a certain budget gives a very poor return.
>
> Graham
>
>        [[alternative HTML version deleted]]
>
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>

	[[alternative HTML version deleted]]

