Why are the variables in the benefits part of the index multiplied rather than weighted and added?
The BCI has been carefully designed to be logical and conceptually as close as possible to a Benefit: Cost Ratio. Multiplication of the benefits variables is a key part of that. As a reminder, the benefits part of the index is: V x W x F x A x B x P x G x DFB(L) x 20 This formula consists of four types of elements: (i) The value score, V, out of 100. This is the factor that makes it possible to compare BCI values for different assets (see FAQ 603). It scales the results relative to the significance (or importance, or value, if you prefer) of the asset. For example, if asset X is considered to be twice as valuable as asset Y, we assume that a project that prevents a 10% loss of value of X delivers benefits that are worth twice as much as a project that prevents a 10% loss of value of Y. It is important that the scores provided for V are standardised. In INFFER, we define a score of 100 as the value of an asset of very high national significance. All other assets are defined relative to
