《Fundamentals of Project Management 4th Edition》 读书笔记 第八章 制作一个可行的进度安排

CHAPTER 8 Producing a Workable Schedule

大多数情况下，我们会被告知项目要在什么时候结束。在某些条件未满足的时候，项目也不能开始。所以我们的工作往往是，在两个固定的时间点间填满工作，并完成项目任务。如果不能在两点间完成，则需要想办法对关键路径进行缩短。

Naturally, in most actual work projects, wehave been told when we must be finished. That is, the end date is dictated.Furthermore, the start date for the job is often constrained for some reason:resources
won’t be available, specs won’t be written, or another project won’tbe finished until that time. So scheduling usually means trying to fit the workbetween two fixed points in time. Whatever the case, we still want to know howlong the project will take to complete;
if it won’t fit into the required timeframe, then we will have to do something to shorten the critical path.

一定要考虑完成任务所需的资源。

Network computations must ultimately bemade with resource limitations in mind. Another way to say this is thatresource allocation is necessary to determine what kind of schedule is actuallyachievable! Failure
to consider resources almost always leads to a schedulethat cannot be met.

将加班时间考虑到项目进度里去是不好的做法，一旦出现什么问题，我们就没有任何可回旋的余地来按时完成任务。

It is bad practice to schedule a project sothat overtime is required to meet the schedule, since if problems are encountered,it may not be possible to work more overtime to solve them.

而且加班会带来错误的增加，导致返工。

This is not always possible. Applyingovertime often increases errors, leading to rework, which may mean that youdon’t get the job done any faster than if you had just worked a normalschedule.

向任务里加入更多的资源也不会一直缩短进度，例如增加更多人手，到了某种程度，反而会增加工作周期。

Furthermore, there is always a point ofdiminishing returns when you add bodies to a task. At some point, they just getin each other’s way, actually slowing work down rather than speeding it. Notethat overtime
should be kept in reserve in case of problems, so it is never agood idea to schedule a project in a way that requires overtime just to meetthe original schedule.

所有的组员都应鼓励尽量缩短float，从而应对不可预知的问题。

Another point of great importance: All membersof the project team should be encouraged to keep float times in reserve asinsurance against bad estimates or unforeseen problems.

一旦一个任务的float被用完，则它就成为了关键路径中的任务。

Once you have used up the float on a task,it becomes part of the critical path.

提高效率也是缩短任务周期的一个方法。

It is possible to shorten a task by addingresources, reducing its scope, doing sloppy (poor-quality) work, being moreefficient, or changing the process by which the work is done. With theexception of doing
sloppy work, all of the methods may be acceptable. Areduction in scope must be negotiated with your customer, of course.

要避免完美主义，没有绝对的完美。

Avoid the temptation to perfecteverything—that’s what the next-generation product or service is all about.Note: I did not say it is okay to do the job sloppily or that you shouldn’t doyour best work. I said
don’t be tempted to make it perfect. By definition, youwill never reach perfection.

要尽最大努力保证关键路径上的任务按计划执行，如果能够缩短关键路径上的任务的周期则更好。

Apply whatever effort is needed to keepcritical tasks on schedule. If a task on the critical path can be finishedahead of schedule, do it!

一个人有效的工作时间最多只占所有工作时间的80%，对于知识型劳动者则更短。无效时间由几种原因导致：一是人们需要休息，二是人疲惫后效率下降，三是由于等待。

A major factor in dealing with resourceallocation is the availability of each person to do project work. One guidelinethat industrial engineers follow is that no person is available to work morethan 80 percent
of the time. If you assume an eight-hour day, that means 6.4hours a day available for work and prudence says to just make it six hours. The20 percent lost availability goes to three factors called PFD. P meanspersonal—every individual must take breaks. F is
for fatigue—you loseproductive time as people get tired. And D means delays—people lose timewaiting for inputs from others, supplies, or instructions on what to do.

知识型劳动者的有效工作时间一般只有50%

Experience shows, however, that the onlypeople who are available to work even 80 percent of the time are those whose jobstie them to their work stations. This is true for factory workers and otherswho do
routine jobs like processing insurance claims (and even these peoplemove around). With knowledge workers, you never get 80 percent of a day inproductive work. The figure is usually closer to 50 percent, and it may belower!

各种打扰导致工作的中断，从而导致工作时间减少，进而导致加班，加班导致工作效率下降。所以一定要减少对工作的打扰。

The usual solution is that people must workovertime to get their project work done because of all the disruptions thatoccur during the day. The problem is that studies have found that overtime hasa very negative
impact on productivity. So it is a losing battle. Short-termovertime is fine, but long spans just get organizations into trouble.