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Overview:
There are two popular methods for tracking the progress of
tasks in a project schedule: Tracking by percent complete and tracking by work
remaining. Both methods have their pros and cons but the latter method often
proves more effective in schedule management.
Tracking Tasks by Percent Complete:
The basic premise of tracking by percent complete is that if a task is
given two weeks in which to complete and one week has already passed, then the
task is 50% complete. The upside of this method is that it is easy to manage
because you do not need to gather information from anyone in order to compute
it. The downside is that it is very inaccurate in most cases. In
order for this method to work, progress needs to made evenly throughout the time
allotted and without interruption. Unfortunately, most projects do not work
this way. Resources are often pulled away to work on other tasks and they
may devote less time than planned during the first week. While the simple
calculation would assume that 50% of the work is complete, in reality, only 25%
of the work may be complete. Just because the time has elapsed does not mean
that progress has been made.
An alternative way to use percent complete is to ask the
person assigned to the task what percentage they are complete with the task.
This alternative method is more effective than simply relying on elapsed time,
but it is still highly subjective. When the person who is assigned the
tasks says that he is 90% done, on what does he base this assessment? He
may be basing his assessment on a feeling that most of the work is done and
there is just a bit more work to do relative to what has already been done.
However, this assessment is typically based on the remaining amount of real work
relative to the total amount of real work. It is not based on schedule time and
does not take into account any elapsed schedule time in which no progress was
made. So the project manager does not have enough information to determine
whether or not the task is on schedule.
Tracking Tasks by Work Remaining:
Project managers often ask the people assigned to tasks if they believe
that their tasks will be completed on schedule. To answer this question,
the person assigned to the task must assess how much real work is remaining and
if that work can be completed by the schedule date. If the amount of
remaining work does not exceed the amount of time allocated in the schedule then
he will answer "Yes, the task will be completed on schedule". Many project
managers ask two questions: "What percent complete is the task?" and "Will the
task be complete on schedule?". Is there still value in asking about the
percent complete if the answer that you get is based on actual work time and not
schedule time? The answer is there is value, but not necessarily for
schedule calculations. The value of knowing the percent complete based on real
work is that you can use it in conjunction with the assessment of remaining real
work to figure out the level of risk in the assessments. If a 10 day (real
work) task is 95% complete and the person states that there are 4 days of
remaining real work left, then you should question both assessments to determine
if the person is being distracted by other work. These basic questions will
guide your follow up questions more effectively.
Conclusion:
What a project manager really wants to know is
"How many total days of real work does the task require?", "How many days of
real work are remaining?", and "Can the remaining work be done by the scheduled
finish date?". The key here is that just because the person has 2 days of
remaining real work does not mean that he will complete this work in 2 days.
Asking these question regularly will allow you get a better sense of true
percentage complete and allow you to adjust your schedule to accommodate
situations in which the person assigned to the task is not 100% focused on the
task. This method of tracking the progress of tasks is an more effective
indicator of schedule health than simple percentage complete based on schedule
time.
Published on October 2, 2010
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