• For many tasks, it is very difficult to evaluate a completion percentage. When is an engineer’s design for a new motor assembly 50% complete? Or when is a programmer’s code for a software module 50% complete? Reporting work in progress is in many cases a “best guess” effort and inherently risky.

• The elapsed portion of a task’s duration is not always equal to the amount of work accomplished. For example, a task might require relatively little effort initially, but require more work as time passes. (This is referred to as a backloaded task.) When 50% of its duration has elapsed, far less than 50% of its total work will have been completed.

• The resources assigned to a task might have different criteria for what constitutes the task’s completion than the criteria determined by the project manager or the resources assigned to successor tasks.

Good project planning and communication can avoid or mitigate these and other problems that arise in project execution. For example, developing proper task durations and status-reporting periods should help you identify tasks that have varied substantially from the baseline early enough to make adjustments. Having well-documented and well-communicated task completion criteria should help prevent “downstream” surprises. Nevertheless, large, complex projects will almost always vary from the baseline.

1. Top-Down planning. Identifies the major phases or products of the project before filling the tasks required to complete those phases. Complex projects can have multiple layers of phases. This approach works from general to specific.
2. Buttom-Up planning. Identifies as many bottom-level detailed tasks as possible before organizing them into logic groups, called phases or summary tasks. This approach works from specific to general.

Creating accurate tasks and phases for most complex project usually requires a combination of both top-down and bottom-up planning. It's common for a project manager to begin with estabilished, broad phases (top-down) and for resources who will execute the project to provide the detailed tasks and fill out the each phase(bottom-up).

1. Overall project duration often correlates to task duration.
2. Level of detail for tracking project progress. If you have a multi-year project, it might not be practical or even possible to track tasks that are measured in minutes or seconds. In general, you should measure the project duration in the lowest level or control that is important to you, not lower.

Good sources of task durations include:

• Historical information from previous, similar projects
• Estimates from the people who will complete the tasks
• Expert judgement who managed similar projects
• Standards of professional or indurstrial organizations that undertake projects similar to yours

For complex projects, you probably need to combine these and other resources to estimate task durations. Because inaccurate task durations are a major source of risk in any project, making good estimates is well worth the efforts expanded.

One general rule of thumb to consider is 8/80 rule. This rules suggests that a task duration between 8 hours to 80 hours are generally sized to a managable duration. Tasks shorter than one day might be too granular, and tasks more than 2 weeks might be too long to be managed properly. There are many legitimate reasons to break this rule, but its guidelines are worth considering for most tasks in your project.

目前的项目环境需要项目经理的领导技术。项目经理的领导技术包括一下元素：

1.       个人，项目和公司层面的目标和方法

2.       通过沟通管理实现目标和方法在所有从层面上的一致性。这里的一致性是指方法的最终目的是为了实现目标。

这些听起来像是一些你从来都没有做过的事情，但是相信我，基本上每天你都在这么做。

示例：追逐幸福是你的目标

（这只是个示例，不是一个道德辩论）

如果在现在的社会中，努力奋斗实现这个目标的标准方法有：

1.       获得教育

2.       找到一份工作

3.       结婚

4.       生孩子

实现目标的唯一前提就是：你的合作者和你有共同的观点。至少你们的目标是大致相同的。如果他们的目标的实现是建立在摧毁你的目标的基础上，你就有麻烦了。

我们都知道这需要大量的沟通才能够实现。

不同的方法

如果你决定使用非标准的方法来实现你的目标，你可能会被看成是一个不错的异乎寻常的人。例如在学校的时候跳级。如果你能够成功，人们会叫你怪才，而且你也会是与众不同的接触的人。

如果你使用完全怪异的方法，遵照一种全新的生活方式，你可能会被大家排斥，也会被看成是与众不同的人，但是以一种不好的方式。

在社会环境中，使用一种不占统治地位的策略，或许是成功的根源。但是在一个项目中，通常都不是有益的。

适量的采用不同的方法可以产生独一无二的效果。如果过分的采用不同的方法就会造成冲突。