w吉姆·奥布赖恩（Jim O’Brien）在1960年代促进关键路径管理的概念上是否如此成功，但是今天，许多承包商宁愿恢复到酒吧图表吗？条形图（或甘特图）是在1910年发明的，这是对先前制作待办事项清单的现有艺术的巨大改进，并可能以优选的序列大致重新排序。它允许用户创建任务或“活动”的真实“时间表”，包括估计的持续时间，首选（通常是早期）开始和结束日期。将活动放在特定日期的安置是通过单独或与他或她的团队的直觉来完成的，他们弄清楚了一个活动的完成可能会影响另一个活动的开始。

除了最简单的项目外，还需要做好的工作，需要大量的努力。18luck官网但是，这种对逻辑的考虑很少被记录。

If even minor changes were made to the scope, or actual durations and progress did not match those initially anticipated, the team was required to meet again to re-create (or using today’s jargon, “rebaseline”) the bar-chart schedule, often requiring more than 40% of the initial effort.

吉姆·凯利（Jim Kelly）和摩根·沃克（Morgan Walker）于1956年开发了数学，与约翰·莫克利（John Mauchly）（设计了第一个通用电子数字计算机）创造了一种记录团队讨论的逻辑并自动化早期日期的逻辑的手段。这些日期代表了最早的日期，即预计一项活动可以开始和结束（基于逻辑和持续时间），并将其留给校长，以根据可用资源起诉某些人并推迟其他人。作为附加的好处，计算机还计算了较晚的日期，代表了以指定日期或尽早完成项目所需的最新开始和结束。

现在对早期和晚期日期的审查有助于主管部署资源，并确定尽快执行哪些活动，哪些活动允许“浮动”朝着按计算的晚期日期设定的“ Drop Dead”截止日期。因此，某些活动的绩效必须尽快开始和完成，并认为对及时的项目完成“至关重要”，而其他活动则可以“浮动”以实现最佳的资源部署，但要遵守及时完成的​​主要目标。Initially called the “Kelly-Walker Method,” this procedure was rebranded as the “Critical Path Method” or CPM and sold to the world by Jim O’Brien’s book, CPM in Construction Management (1964: McGraw-Hill.) Notice well the primary goal of the contractor and its superintendent: to complete on-time or even earlier if possible.

Unlike the world of manufacturing, construction usually permits the contractor to bring in additional resources as needed, to use or hold in reserve, release and then if necessary to bring back, without regard for “best use of the resource,” and all to support this primary goal. And both the mathematics and initial computer instruction programs were specifically developed to support this primary goal.

This is why Jim O’Brien and others were so successful in selling this new concept to contractors.

尽管额外的工作要求“为什么必须在B之前完成A”并以一种奇怪的格式记录该逻辑以便将其输入计算机，但协助构建首选时间表的好处，以及实际上与预期的，实际上相差的快速重新计算出售了这个概念。承包商急于没有所有者的要求实施这个新想法 - 这是按照承包商的安排。CPM建筑管理中的CPM成为了McGraw Hill专业系列的畅销书（并仍然是）。

降低使用CPM的热情发生了什么？在美国诉公民和南部国家银行，367 F. 2d 473（1966）中，分包商和承包商都能够表现出由于不承担任何责任的因素而造成的延迟损害。如果没有明确的证据将这两个索赔分开，法院驳回了这两项索赔，并指出：“由于证据没有为在这些贡献因素中分配额外费用的任何合理依据，我们得出结论，整个索赔应该被拒绝。18luck.cub透明但随着CPM的出现，情况发生了变化。早在1963年至1964年，涉及原子能委员会案件两侧的诉讼人的顾问就使用了CPM来准备其职位。到1967年，其他法院也以CPM为决定的基础。

Separation of Competing Claims

到1972年，法院要求将CPM时间表用作延迟指控的基础，以便将竞争性索赔分开，如（Minmar Builders，Inc.，GSBCA，GSBCA的上诉3430，72-2 BOA。）可以用作武器，而不是用作工具，而是开始改变其主要目的的第一个努力。1956年的数学和用于支持CPM的软件一直被认为具有公差和近似性。但是在法庭上，“专家”准备的打印输出和展品仅提供了“计算机这样说，因此必须如此。”需要允许政党将计算汇总到所需结果的软件，并由愿意的供应商提供。仅在极少数情况下可能适当的选项被添加 - 并且未按照打印输出的方式报告。

And only now did owners (to their contractors – or contractors to their subcontractors) begin to require a CPM of their subordinate, and with the purpose to “game the claim” rather than “provide additional assurance that the subordinate can complete on time.” As owners demand the CPM and specify software to be used, so the developer of the software has a new voice dictating new features. The software is no longer of, by and for the contractor.

Concurrently, others outside of construction viewed the “computer-drawn bar chart” and desired the same for their business use neither knowing, understanding nor caring that CPM calculates two schedules (early and late) from which the team leader (or superintendent) is advised how to deploy resources for a working schedule. An alternate algorithm based on best (usually continuous) use of fixed resources (whether machines of iron or computer coding personnel chained to their cubicle) was incorporated, perhaps even knowing that would delay the project, but for a possibly lower cost.

修改的软件

在这一点上，主要软件开发人员必须选择在哪里放置编程资源 - 为35,000名购买350,000个许可证的建筑客户服务或为购买100万个许可证的5,000名IT客户提供服务。与5,000名决策者会面，他们每个人都可以购买数千个许可证要容易得多，而且销售的生产力要高得多。软件公司修改了其产品，以添加5,000个功能。5,000的高层管理人员不希望无关紧要和“令人困惑”的选项，因此删除了1956年的原始算法。

Owners specifying CPM for construction did not care that software may not assist a contractor so long as it may hamper claims. Contractors finding software did not assist earliest completion now provide minimal effort to prepare the submittal required for payment, while falling back to simpler tools to actually manage the project. And so today many contractors have reverted to bar charts and other tools to display their preferred (if not most likely to bring in the project on-time) schedule.

制造业的咒语,最佳的生产力the unit or activity or of the individual, has eclipsed attempts to achieve the best (or fastest) project and the very concept of team effort. So our challenge is to again teach construction contractors and others desiring earliest completion of projects, from the superintendents in the field to the professional managers in the boardrooms, that the mathematics and discipline of CPM, coupled with proper software to solve this problem and not those of others, will deliver return on the intellectual effort required.

我认为吉姆同意，今天比1960年代初期可能会更加困难。