<P> The value of a cost--benefit analysis depends on the accuracy of the individual cost and benefit estimates . Comparative studies indicate that such estimates are often flawed, preventing improvements in Pareto and Kaldor - Hicks efficiency . Causes of these inaccuracies include: </P> <Ul> <Li> Over-reliance on data from past projects (often differing markedly in function or size and the skill levels of the team members) </Li> <Li> Use of subjective impressions in assessment </Li> <Li> Inappropriate use of heuristics to derive money cost of the intangible elements </Li> <Li> Confirmation bias among project supporters (looking for reasons to proceed). </Li> </Ul> <Li> Over-reliance on data from past projects (often differing markedly in function or size and the skill levels of the team members) </Li> <Li> Use of subjective impressions in assessment </Li>

When will a cost benefit analysis be done