Institutional RepositoryThe Digital Knowledge digital repository system captures, stores, indexes, preserves, and distributes digital research material.http://digitalknowledge.cput.ac.za2019-05-24T09:37:16Z2019-05-24T09:37:16Z5011A rework probability model: a quantitative assessment of rework occurrence in construction projectsSimpeh, Eric KwameNdihokubwayo, RubenLove, Peter EDThwala, Wellington Dhttp://hdl.handle.net/11189/33702018-11-12T10:01:09Z2015-01-01T00:00:00ZTitle: A rework probability model: a quantitative assessment of rework occurrence in construction projects
Authors: Simpeh, Eric Kwame; Ndihokubwayo, Ruben; Love, Peter ED; Thwala, Wellington D
Abstract: Statistical methods for eliciting probability distributions were used to analyse the data collected from 78 construction professionals. The empirical distributions for rework costs were found to be non-Gaussian. Theoretical probability distributions were fitted to the rework data. Non-parametric tests were used to determine the goodness-of-fit of the selected probability distributions. The results of the goodness-of-fit tests revealed that generalized Pareto distribution provided the best fit for the dataset. Single probability points for rework from 1% to 10% were calculated. It was established that rework can make a significant contribution to a project's cost overrun. The mean total rework cost as a percentage of the original contract value was found to be 5.12%. For a mean total rework cost of 5.12% the likelihood that a project exceeds is 76%. The anticipation that rework will occur, using the probabilities that are derived, can enable a quantitative risk assessment to be undertaken, which will ultimately lead to identifying alternative solutions so as to avoid rework prior to the commencement of construction work.
2015-01-01T00:00:00Z