The biggest challenge in the use of Microsoft Project

What is Project, and what isn’t it?

Microsoft Project is a very misunderstood application. It is reminiscent of other Office applications, with menus and toolbars like Word, and tables and graphs like Excel, but when you get into it, you see it’s very different. In some ways, it seems to do things on its own.

Project is the most narrowly focused of all the Office applications. While the other Microsoft Office programs tend to be broad and general in their application, Microsoft Project is designed exclusively to manage resource usage and project scheduling.

It will not manage your project for you. It will not stop you from giving your resources too much to do. It will not tell you what is going to happen, but it will let you know what might happen if nothing changed. Just like any other software, Project should be used as an informational system and not as a crystal ball.

Project will help you keep track of the progress of your tasks. It will help you figure out how much each of your resources is doing on your project. It will make it easier to communicate the status of your project.

If you’re new to Project or considering this software as a solution, I’ll explain the basics of Microsoft Project over the next few articles. Let’s begin with a look at how Microsoft Project calculates Work, Duration, and Units.


Duration = Work/assignment Units
The calculation of Work, Duration, and Units is the single biggest trouble spot for new users of Project. This calculation is the core of what Project does and it cannot be turned off, so you must deal with it.

Duration = Work/assignment Units: This equation is the E=MC² of Project. It means that, given the other settings in Project—like how many hours in a day, etc.—the assignment Duration (in hours) is equal to the assignment Work (in hours) divided by the assignment Units value. Units are the percentage of a resource’s workday, or the amount of the day the project team member is expected to work on a given assignment. For example, if you want Joe to work half-time on a task, you would assign him at 50 percent Units.

If a resource’s workday is eight hours and he or she is assigned to work on a task at 100% Units (for eight hours of work), then the Duration is eight hours (one day by default).

Now let’s say you change the Units to 50%. Then the Duration becomes 16 hours or two days, because if a person is working half of an eight-hour day on this task, then it will take them 16 hours (two days) to complete eight hours of work.

Lots of people will attempt to argue with this formula, but save your breath and time by just accepting it. It is a Microsoft Project truism, and even if you do not agree with it, this formula is what Project uses.

Everything that Project does is based in some way on the calculations that this formula makes.

Task types
The way that Project gives you some control over how this formula affects your Project is through the task type function.

The task type options are:

Fixed Units
Fixed Work
Fixed Duration

As you might guess from the names, they allow you to “fix” one of the three elements of the equation in order to control what will be adjusted to make the two sides equate.



The Advanced tab on the Task Information menu allows you to choose whether you’d like to fix the value of Units, Work, or Duration.



As you’ll recall from junior-high algebra, if you have a three-element equation and you hold one value fixed, then if you change a second value, the third value must change to keep the equation true. For example:

1 day Duration = 8 hours Work /100% Units

If we create this as a Fixed Duration task type and then change the Units to 50%, Project automatically will change the Work value to four hours.

If we set the task to Fixed Work, then the same change in Units would cause Project to adjust the Duration value to two days. And, if we set the task to Fixed Duration and edited Work to 16 hours, Project would adjust the Units value to 200% in order to keep the Duration value fixed yet still balance the equation.

That said, the best way to become familiar with this function is to create a test Project, play with the settings, and see how Project reacts to changing data or adding actual work.


This article is an exeprt of many at: http://articles.techrepublic.com.com/5100-10878-1031576.html

I do not take the credit...

Now, here is how it works for me:


-Got to make sure to properly fill in the resources holidays from the Change working time window.


-Always double check that the resources do not have more than 100% (Yes it appens)


-Add the column Work to your regular view. I suggest you add it to the left. First after description.


-Modify your options to have the Task Type set to WORK and not DURATION.
This is very important. If you are a real project manager ;-) , that will also help you to properly calculate you costs and ETC (estimate to complete (ETC=EAC-AC)).

Keep in mind that ONLY the NEW tasks will be created using the newly modified setting. Means you need to change all te old tasks if you need to get them using Type WORK.

Why?: The field (value) to calculate the costs is WORK.
If you keep task type to DURATION, the WORK value will always change when you modify duration.
Your plan will always get wrong and you'll scream on Microsoft ;-)


-If the WORK/DURATION/"Percentage on the resource" are screwed, you need to enter "0" for DURATION AND AFTER You enter "0" for WORK (DO not delete the value of the field and do it in that order).
Than you can start over and enter the new value for Work. If you do it in another way, you might get the resources at 200% or somehting like this.

-Also remember that Effort is Work. Will help you to understand the concepts.

-If you schedule days off in the working time, you absolutely need to set the calender option in the task. I use "Standard". If you do not do it, it won't allow the calculation to skip the days off to set your finish and start date.

However, using task type "WORK", The duration will not take into account the days off.

For Exemple, you have 2 days of work starting July 1st. You set 2 days off for July 2nd and July 3rd. You will get different results depending on your setting and the number of resources (Of course, that is why it is so hard at first). If you use Task Type WORK and calendar to standard, you set one resource, WORK to 2, you will get a DURATION of 2 BUT the finish date will be July 4th.

If you select Ignoire resource Calendar, the finish date is July 2nd.

If you set Tasks type to Duration (not WORK), the Duration field will become 4, still with the finish date to July 4th.

Keep in mind that Taks Type to work CAN take into account the calendar but the total nmber of days will not count the days off. Tasks Type to Duration WILL count the days off in the total days.


Have fun.