I was a fortunate young developer. In my first three months at work, I ran into the 90% done schedule game. I did it to myself.I estimated a particular task was going to take 6 weeks. Of course, being an arrogant and naive developer, it never occurred to me to break the task down into inch-pebbles. (That would have told me whether I even knew what to do for the task.)

At the end of the first week, I was 20% done. At the end of the second week, I was 40% done. At the end of the third week I was 60% done. At the end of the fourth week, I was 80% done. Right on time, at the end of the fifth week, I was 90% done. At the end of the sixth week, I was 92% done. Seventh week, 93% done. Time and I both marched onward. At the end of the 10th week, I was 97% done. But this time, I actually believed I was within a week of being done -- I only had three one-day tasks left to complete. It took me two more weeks. A total of 12 weeks for a 6 week task.

(一个大粒度的任务到达个人后，对于个人一定要认为这个大粒度的任务就是一个完整的项目，要有计划，有WBS分解，有相应的里程碑和检查点。不要太狂妄自大和天真，不要太相信自我的经验和直觉，特别是对于复杂的问题，周期跨度较长的项目我们的经验和直觉往往会失效。在这里我们会再次强调挣值的0-100法则，对于一件事情及时你反馈完成99%，但是只要没有100%完成，没有通过最后的验收你仍然得不到一丝的报酬。90%完成也是一种进度欺骗，可能是你欺骗 了你的领导，也可能是你欺骗了自己，你自己的经验和你开了一个玩笑。看上面作者的例子可以看到，一个估算为6周的工作，完成90%的时候花费了6周，而完成最后的10%又花费了6周。)

During the time I was 92%, 93%, 94% done, I wrote status reports to my manager, explaining I'd run into unanticipated problems and that I hadn't estimated all the things I needed to do. He was lovely about it, and kept saying, "Ok, let me know your updated estimate."(不知道大家有没有做一件事情或任务，做到后面越做越复杂的体会。出现这种问题的原因不仅仅是估算不足或者是风险管理没有做好。这是一个涉及到个人计划和任务管理的一个复杂的系统问题。)

At the end of this task, when I was finally done, he was all set to move on. I told him I would be estimating differently from now on, with much more detail, and several deliverables each week. If I couldn't give him a date to be done, was that ok with him. We talked and I agreed to supply a date with a risk factor with each estimate.

I wish I could tell you I became a perfect estimator then. I didn't. I'm still learning to estimate. But I now know that when I think I'm 90% done, I'm probably only 50% done.

(根据经验你任务90%的任务完成而实际情况往往只是完成了50%的工作任务。90%的任务完成改进的焦点在估算方法和风险管理两个方面，而估算方法的改进首先则是要有一个完善的WBS工作任务分解。)

I'm not the only one. The 90% done schedule game can occur under any conditions: reasonable or unreasonable schedule, low or high risk technology. 90% done is about our ability to predict the future, to perform accurate estimation, and to understand -- in advance -- if we will be interrupted. Not a trivial problem.

The 90% done schedule game is the reason I like feedback during project work, in the form of inch pebble estimation, one-on-one meetings with managers, visible project status, and project-wide rolling wave planning.

(如何解决90%任务完成的问题，作者在文章开始就已经指出了具体的方法，即break the task down into inch-pebbles。即要把一个大的工作任务分解为一个个的细粒度的子任务，在分解为子任务的过程中有两个核心要素是需要强调的，第一个是每个子任务都需要有明确的产出物进行验收；第二个是我们强调的是迭代而不是增量，因此任务切分的方式是横向的而不是纵向的。举例来说如果一个软件开发有10个较为独立的功能点要做，则我们需要的分解是每各个功能点什么时候能够全部完成需求，开发和测试。如果你的分解方式是10个功能点都完成需求，都完成设计等，这种子任务的分解方式对我们来说仍然是属于进度不明朗。计划和任务管理和我们平时做事情的思维模式是一样的，所有任务都去做一点还不如一件事情一件事情的做完做好。)