How Microsoft Project Thinks of different Task Types????

There are a number of factors that dictate how Microsoft Project “thinks”.

The two main factors are:

  • The Scheduling Formula
  • The Task Type

The scheduling Formula leverages three variables:

  • Units – The percentage of time required by a resource or resources to complete the task
  • Duration – The number of working days required to complete the task
  • Work – The effort required to complete the task

e say that the scheduling formula is: Units x Duration = Work

When you initially assign a Resource to a Task, this is the formula that is leveraged. Let’s demonstrate:

We will create Task 1 that is 5 days in Duration

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We will now assign a Resource to this task

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As soon as we assign this Resource to this task, Work changes to 40 hours.

Here is the how that number was calculated:

Units x Duration = Work
100% x (5*8) = 40
Or
100% x 40 = 40 hours

But using simple math, we can re-write our equation to solve for a different variable.

Our original formula solves for Work:
Units x Duration = Work

But we could re-write the formula to solve for Units:
Work / Duration = Units

Or we could re-write the formula to solve for Duration:
Work / Units = Duration

So we have shown that The Scheduling Formula can actually be written three different ways:

Units x Duration = Work
Work / Duration = Units
Work / Units = Duration

Now let’s prove that Microsoft Project also thinks this way.

In order to demonstrate this, we must introduce The Task Type or the Type field:

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By default, Type is set to Fixed Units. But there are actually three different Task Type variables:

  • Fixed Duration
  • Fixed Units
  • Fixed Work

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Now to test Microsoft Project

Using our original scenario, let’s force Microsoft Project to solve for Duration.

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We will leave Type set to Fixed Units and change Work to 80 hrs

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Here is how Duration was calculated:

Work / Units = Duration
80 / 100% = 80
Or
80 / 100% = (80 / clip_image008
Or
80 / 100% = 10 days

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Returning to our original scenario, let’s force Microsoft Project to solve for Work.

clip_image006[1]

Leave Type set to Fixed Units and enter 10 days Duration

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Here is how Work was calculated:

Units x Duration = Work
100% * 10 days = 80
Or
100% * 10 days = (10 * clip_image008[1]
Or
100% * 10 days = 80 hours Work

clip_image011

Returning to our original scenario, let’s force Microsoft Project to solve for Units

clip_image006[2]

Change Type to Fixed Duration and enter 20 hours Work

clip_image012

Here is how Units was calculated:

Work / Duration = Units
20 / 5 days = 50%
Or
20 / 5 days = 20 / (8 * 5)
Or
20 / 5 days = 20 / 40
Or
20 / 5 days = 0.5

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The Task Type and Scheduling Formula Cheat Sheet will help you control how Microsoft Project “thinks”:

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