Olsson, Nils O. E.; Magnussen, Ole M.: Flexibility at Different Stages in the Life Cycle of Projects: An Empirical Illustration of the Freedom o Maneuver“; in: Journal of Project Management, Vol. 38 (2007), No. 4, pp. 25-32.
The conceptual model, that uncertainty and degrees of freedom decrease during the life cycle of a project whilst the actual costs increase, is nothing new. New is the empirical proof. Olsson & Magnussen are the first to measure the degrees of freedom. They use the governmentally required reduction lists as a measure for the degrees of freedom in public projects.
Moreover they recommend a funding system which gives the project manager control over the basic budget and the expected additional costs (e.g. the value of the risk register). On top of this funding go the reserves or contingencies, which typically are about 8% of the total budget and which are managed by the agencies. Then comes the reduction list, which usually is 5.9% of the budget in the beginning of the project and reduces to 0.8% at half time. The authors argue that such a funding system has 85% probability of being kept.