Business achieve their strategic objectives by running projects.

Projects are comprised of many tasks.

Tasks can be categorised into three main groups, this blog defines those groups.

Project Management Task Types Defined

The three main task types that exist in project management are:

  • Fixed Work Tasks
  • Fixed Duration Tasks
  • Fixed Units Tasks

Each of these three will now be discussed in more detail.

Fixed Work

A fixed work task has a fixed amount of work. As an example:

The estimate to paint a room is 40 hours of effort. The work content is therefore 40 hours. Let’s assume an 8 hour working day:

  • If there is 1 person on the task it will take 40 hours. (5 days duration)
  • If there are 2 people on the task it should take 40 hours (20 hours each) but completed in half the duration. (2.5 days duration)
  • If there are 4 people on the task it should still take 40 hours (10 hours each), and completed in a quarter of the duration – providing there are enough paintbrushes, ladders, paint pots etc. (just over a day’s duration)

In all of these examples, the work – 40 hours – does not change – it is fixed. The duration will change depending in the number of resources.

There is often a diminishing return on adding extra workers – if we had 100 painters, there would be chaos, and the job would not be finished in 24 minutes!

Note that the cost should remain the same. Paying 1 person for 40 hours is the same as paying 4 people for 10 hours of work (providing people are paid just for the work done, and have other work to do when not required! This will be true when resources ‘book time’ to a particular project.)

Care should be taken to consider the task and the effect of adding more resource.

Writing software code may be a 40 hour task for 1 person. However, if two people are assigned to the task, then they have to talk, communicate, agree variables, and test that their finished software operates successfully together. This may increase the work content to 50 hours (adding extra cost), but two people working on a 50 hour task (25 hours each) should be quicker than 1 person working on a 40 hour tasks.

Fixed Duration

A fixed duration task has a fixed duration no matter how many resources are applied to it. Examples include:

  • Concrete Drying
  • Electrical or chemical soaking tasks
  • Paint drying
  • Transportation

The duration of these tasks cannot be reduced by adding more resources, as they are ‘Fixed Duration’ tasks. They have a set time that they must take before completion.

Fixed Units

These tasks require a set number of resources in order to take place.

  • A lecture requires at least one lecturer and at least 1 student
  • Setting up a machine may need one operator and 1 quality inspector
  • A task may require a room booking and certain people to be present

These tasks will also have a work (effort) content and duration – but need the resources to be present to take place.

Understand the Task Type

It is vital that a project manager is aware of the tasks types in their projects. The task type is a key factor in deciding if more resource can be added to the task to reduce the duration. Task types also have a major importance in the way that Microsoft Project is used.

Task types: Fixed Work, Fixed Units, and Fixed Duration: Understand the task types in your project, and the implications of adding more resources to ‘Fixed Work’ type tasks.


Posted On: 25th January 2018

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