Evaluation of Mean and Variance Approximations in Three Point Estimation of Task Completion Times Using the Beta and the Kumaraswamy Distribution

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Inderscience Enterprises, Ltd

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International Journal of Information Technology and Management

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Estimation of task and project completion times within IT projects remains one of the most error-prone, but also most critical duties of an IT project manager. Various three-point methods of PERT have been evaluated by assuming that the true distribution is a beta-distribution. We evaluate PERT methods by comparing additionally with the Kumaraswamy distribution, which has an equal claim to be the true a-priori distribution for project completion times. We use skew and kurtosis in order to define test sets instead of simply choosing a range of shape parameters. We validate various approximations proposed in the literature and show that valid approximations are possible.


International Journal of Information Technology and Management, Vol. 18, No. 4 (2019):389-406. DOI.