Approaching activity duration in PERT by means of fuzzy sets theory and statistics

Taking into account the intrinsic drawbacks of both classic and fuzzy PERT, the authors present a new approach in an attempt to deal with them. The tools for this approach are fuzzy statistics and fuzzy probabilities. A necessary condition for this approach is the existence of statistical data for the project activity duration. The final findings are the fuzzy activity times (earliest/latest start - earliest/latest finish), the fuzzy float, the Criticality Degree both for each activity and for each path, a fuzzy probability for the activity duration to be in a certain time interval and a fuzzy probability for the project completion time to be in certain time interval. A numerical example is provided for thorough comprehension.