When it comes to task types, there’s absolutely no reason to have a chart or "cheat sheet" to anticipate what MS Project will do when duration, work or resources are changed.

First of all, there is absolutely no difference between a fixed work task, a fixed duration task or a fixed units task. They are all the same and they all behave in the same predictable fashion.

Work = Units * Duration

It’s that simple.

If you put 3 resource Units on a task for 4 days Duration then the Work is obviously 3 * 4 or 12 work days.

If you changed the resource Units on the task to 7 then the Work is obviously 7 * 4 or 28 Work days

If you changed the Duration to 5 days then the Work is obviously 3 * 5 or 15 work days.

So ... why have different task types? Suppose you changed the Work to 30. What is Project going to do? It could be 6*5 or 3*10 or 2*15 or, even, 30*1. (Side note: what Project does is actually quite repeatable -- that’s why some people waste their time building these little cheat sheets: they don’t have to remember the answers, they just look up the routine.)

Here’s the real approach:

Back to the original example:

Work = Units * Duration
12WD = 3U * 4D

Set the task to Fixed Work. That holds "12WD" fixed.
If you change Units then Duration can be calculated.
If you cand Duration then Units can be calculated.


Set the task to Fixed Units. That holds "3U" fixed.
If you change Work then Duration can be calculated.
If you cand Duration then Work can be calculated.

Set the task to Fixed Duration ... oh, heck, you can figure that one out on your own.

So ... forget cheat sheets, forget memorizing. All you need to know is that when you set the task to Fixed Work, Fixed Units or Fixed Duration you are holding one element of the equation constant. When you change the second element of the equation the third element is easy to calculate. Hmm, perhaps you do have to memorize one thing:

Work = Units * Duration


It’s only rocket science when you work for NASA.

Red,

What I think has happened is that is that the Task Type for your activities are either set to Fixed Work or Fixed Duration / Effort Driven. As a quick fix try the following.

Tools > Options > Schedule Tab
Change the Default task type to Fixed Units
Un-check the New tasks are effort driven box
Click ’Set as Default’
Click ’OK’

Now before trying this bit, you may have to remove all your resource from their allocated tasks and change the task durations so they fit in with your expected dates.

Insert > Column
Select Type as the Field name
Click ’OK’
Insert > Column
Select Effort Driven as the Field name
Click ’OK’

In the Type column change all the cells to Fixed Duration (some of the summary ones you might not be able to change, but you only really need to change the cells that affect activities anyway.)
In the Effort Driven column change all the cells to No (you might not be able to change the summary cells, the same criteria as the Type column applies.)

As long as the durations are correct, you can now add as many resources to your tasks as you like and the durations will not change.

Task types are fundamental to how MS Project works, so you really do need to understand this equation if you want to use it properly.

Work = Duration x Units

Work is the resource effort normally in hours or days
Duration is the length of the activity
Units are the assignment /availability shown as a percentage or decimal

By fixing one of the parameter values, the other two can vary.

If you PM me your e-mail address, I can send you a table that I use which also has a little explanation about Work / Units Duration, or you can use Microsoft Project Help (F1) and search ‘About task types’. This may help you in the short term, but if you want to use MS Project without getting frustrated with the tool, you will probably have to buy a text book to help make life easier.

Regards,

Darren

Red,

You resource the separate activities in the same way as you would if you had humans working on them. If I can simplify – which probably means it will get complicated :)

On your project you have two people, let’s call them ’Bill’ and ’Ted’. You also have two computers. If you name the computers, ’Computer A’ and ’Computer B’, these will now be your other resources ready to be scheduled.

As an example, you have to complete three tasks over the course of two days... if you create a simple project schedule in the MS Project Gantt View you would have something like this:

Task 1 - Data Entry
Task 2 – Data Processing
Task 3 – Review Data Reports

Task 1 - Duration 1d and has a FS relationship with Task 2
Task 2 - Duration 0.5d and has a FS relationship with Task3
Task 3 - Duration 0.5d

Task 1 - Starts Wed 16/04/08 08:00 and Finishes Wed 16/04/08 17:00
Task 2 - Starts Thu 17/04/08 08:00 and Finishes Thu 17/04/08 12:00
Task 3 - Starts Thu 17/04/08 13:00 and Finishes Thu 17/04/08 17:00

In the Resource Sheet view, create four resources Bill, Ted, Computer A and Computer B. You then need to decide what resources are going to be assigned to which task and you might end up with something like:

Task 1 - Bill using Computer A, so you would add them to the Resource tab on the Summary Task Information dialog box.
Task 2 - Computer A and Computer B, add them as a resource
Task 3 - Ted and Computer B, add them as a resource

You can now use the Resource Graph view to see if there is any overallocation. In this example there isn’t any, but if Task 2 and Task 3 were to happen at the same time, Computer B would show as overallocated.

Regards,

Darren

Hi Red,

I’ll take a quick stab at this and you can tell me if I’m heading in the wrong direction.

Are the computer tasks different when operated by humans as opposed to when operating on their own?

What I mean by this is do they deliver different things? (Reports for example)

If they are different, why not create a resource called something along the lines of ’Computer’ and create some tasks that will only utilise this resource.

Assign the new resource to the newly created tasks and you should then be able to see if there is any overallocation.

The only way you will be able to see overallocation displayed graphically in MS Project is if it is a resource.

Regards,

Darren