为什么使用计划评审技术、计划评审技术(ProgramEvaluation and ReviewTechnique,简称 PERT)是项目进度管理的一项常用技术。在编制项目进度计划时,当项目的某些工作任务或者所有工作任务的历时估算事先不能完全肯定时,常常需要综合运用关键路径法和加权平均历时估算法来对项目历时进行估算。这种方法通常选取三组事先估算的数据:最乐观或最短的时间、 Why Program Evaluation Technology, Program Evaluation and Review Technology (PERT) is a common technology for project progress management. When preparing the project schedule, when the project’s work tasks or the duration estimation of all the work tasks can not be fully affirmed in advance, it is often necessary to estimate the project duration through the comprehensive application of the critical path method and the weighted average duration estimation method. This method usually selects three sets of pre-estimated data: the most optimistic or the shortest time,