http://images.amazon.com/images/P/0131407287.01.MZZZZZZZ.jpg
ISBN 0131407287

"Software by Numbers" by Mark Denne, Jane Cleland-Huang 

From the Back Cover 

	 :	Software by Numbers is a significant new contribution to value-based, financially responsible software engineering...
		 :	-- Barry Boehm, Ph.D.,
			 :	Director, USC Center for Software Engineering,
			 :	Creator of COCOMO and Spiral Model

'''Software by Numbers''' describes a ReturnOnInvestment-based approach to selecting and prioritizing software features. The book includes an extensive discussion of its method, IFM (Incremental Funding Methodology), and guidelines on implementing it alongside RationalUnifiedProcess or XP.  

IFM is a perfect fit for ExtremeProgramming. Where XP addresses levels 1-3 on the LevelsOfSoftwareSuccess scale, Software by Numbers addresses levels 4-6.  XP's simple approach to architectural dependencies (EvolutionaryArchitecture) looks like it'll make IFM even easier to implement.

''Although some people may be turned off by the numbers-centric view, I loved the focus on DeliverValue and putting costs into context. I think this book offers guidance for OnSiteCustomer''''''s that XP lacks.  Highly recommended.  -- JimShore''