Ever ask yourself, what Task Type should I use in MS Project?

Are you looking to answer the million dollar question in Microsoft Project: What task type should I use for my tasks? This question can make or break resourcing a project schedule and can cause headaches for those managing those schedules when not properly understood.   Continue reading to better understand this feature and how to greatly simplify the answer to this daunting question.

Lets start with the basics, outlined by Microsoft.  There are three task types in MS Project:  Fixed Units, Fixed Duration, and Fixed Work.  And in addition to those three task types, there is this thing called Effort Driven that can be enabled for each.  First things first, it is important to understand the terms Duration, Work, and Units.  Not just in answering the “million dollar question” but more importantly because these three variables are at the heart of how MS Project works.

First, all three task types have the word “fixed” in front of it  So when dealing with each type of task, know that if something is fixed, then it is constant, and not changing.  Lets define each task type:

Duration is known as business hours or business days.  By default, in MS Project we are working 8 hours a day, 5 days a week, 20 days a month.

Work is also known as effort or person hours and days.  How much effort or time will a person spend executing their assigned task

Units is Microsoft’s way of defining how much of a resource ’s time will be dedicated to do work.

Project uses the following arithmetic equation to define how tasks calculate, based on what task types you use:  Duration = Work/Units.  Now throw in that each task type can be combined with the Effort Driven functionality, and you start the confusion.  Microsoft has a useful chart that tells you what is recalculated based on what task type your using.  But this chart can even be further simplified as you will soon see.

Although adding the concept of Effort Driven to the equation can begin the confusion, what you’re going to learn is that you do not need to worry too much about effort driven.  In simple terms, effort driven equates to the more resources you add to a task, the less time it will take.  For more information, Microsoft defines here.

When dealing with Fixed Duration, Fixed Work,  and Fixed Units, you have the option to enable Effort Driven on Fixed Duration and Fixed Units.  If you select Fixed Work, effort driven is automatically on.  So all in all you have 5 options on how to setup a task.  (Fixed Duration - Effort Driven, Fixed Duration - non Effort Driven, Fixed Units - Effort Driven, Fixed Units - non Effort Driven, & Fixed Work - Effort Driven)  But you know this by now and this is why your scratching your head on which one to use.

So, lets simplify all of this mumbo jumbo, and answer the big question, and do so by letting you in on a little secret…..You do not need to worry about the Fixed Units task type at all.    You can create a dynamic schedule by only using two of the 5 options noted above.  The million dollar answer is to use only Fixed Duration - non Effort Driven and Fixed Work.  Why is that?    Because Fixed Units - Effort Driven works exactly the same way as a Fixed Work task, and Fixed Units - non Effort Driven works exactly the same as Fixed Duration - non Effort Driven.  So we just simplified 5 options into 2, and now there is only one more thing to take into account and your off to create your project plans.

Last thing to ask yourself,  what is driving the activity you are planning?  Is it the Duration (business time) or is it the amount of Work (people time).  This should be the easy part, and will be based on what your task  is and what type of schedule you are creating.  Say your task is a training session, where the duration is fixed, regardless of the number of resources that attend; the duration of the training will not change.  Or is your task driven by work, where you know that the amount of effort to complete the task is fixed, regardless of the number of assigned resources.  It takes 20 hours to  code a software specification, so if I have 2 programmers working on that task, it should take less time than 1 programmer.

Whether your changing the type on a task by task basis, or whether your whole schedule uses the same methodology, by thinking of tasks on your project in simple terms, Duration driven or Work driven, and letting MS Project do the rest of your calculations for you, you are on your way to accurate and dynamic project scheduling.

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