MICROSOFT PROJECT DOES NOT CALCULATE DURATION PROPERLY

If you have ever had the pleasure of working with Microsoft Project you will likely be quite happy with it until you start changing the RESOURCE UNITS percentages (in the TASK INFORMATION pane).  If you make changes you will find that it often miscalculates (or appears to miscalculate) the number of HOURS in WORK.  After reading many many blogs and help files, I was about to give up on this when I found a reproducable process to have it calculate the number of days in DURATION correctly:

1. Make sure the task is set to AUTO SCHEDULE
2. Double click on the task and click the ADVANCED tab.  Set the TASK TYPE to FIXED WORK (see below for definitions) and CALDENDAR to STANDARD (or whatever you want)
3. Type in the name of the TASK (do NOT type in the WORK or DURATION fields)
4. Go the RESOURCE NAMES field and type the names and percentages using the following syntax:
   • name[PercentPersentSign],name[PercentPersentSign],name[PercentPersentSign] and so on
   • Ted[10%],John[40%]    This would mean that there will be a total of 4Hr per day worked on the project (8hr day * [40%+10%])

Click on these screen shots for details:

MICROSOFT PROJECT TASK TYPES:

The three task types used in Project are:

• fixed-unit task: A task in which the assigned units [or resources] is a fixed value and any changes to the amount of work or the task’s duration do not affect the task’s units. This is calculated as follows: Duration x Units = Work
• fixed-work task: A task in which the amount of work is a fixed value and any changes to the task’s duration or the number of assigned units [or resources] do not affect the task’s work. This is calculated as follows: Duration x Units = Work
• fixed-duration task: A task in which the duration is a fixed value and any changes to the work or the assigned units [that is, resources] don’t affect the task’s duration. This is calculated as follows: Duration x Units = Work.

Project uses fixed units by default.

Each of the task types affects scheduling when you edit one of the three elements as follows.

In a	If you revise units	If you revise duration	If you revise work
Fixed units task	Duration is recalculated.	Work is recalculated.	Duration is recalculated.
Fixed work task	Duration is recalculated.	Units are recalculated.	Duration is recalculated.
Fixed duration task	Work is recalculated.	Work is recalculated.	Units are recalculated.

LINKS:

You may find the following links useful if you need more details

 http://www.techrepublic.com/article/microsoft-project-tutorial-duration-and-task-types/1031576 and
 http://office.microsoft.com/en-us/project-help/change-the-task-type-project-uses-to-calculate-task-duration-HP010092039.aspx