A Value Metric is a parameter for measuring (and hence also comparing) value. The most important characteristic of a Value Metric is that it is singular. Any increase in the Value Metric must always be better (in contrast to a measure like Information & Technology (I&T)[1] spend as a % of revenue, which needs to be not too much, nor too little. See chapter on Well-behaved KPIs ).
In rare cases, there may be single factor that dominates, such as a return on investment (ROI), a profit, a time to market. More commonly multiple factors are in play (for example, time, cost and quality) then there must be a defined algorithm to determine the trade-offs between changes in each factor.
Any weighted scoring system is effectively creating a Value Metric. This author argues that applying the Value Metric (allocating scores to options) is a relatively low-grade consulting task. The high-grade consulting is to create and establish the Value Metric – to gain political consensus to the weighting factors and grade scales for scoring.
[1] There has been much debate about the differences between information systems, information technology, digital etc. This book treats them as synonymous.