Duration doesn't match the length of its Gantt bar

[Erkki Piipari]

Hi again

Here's my case:
- a task with work for 2 days and duration equals 2 d
- I change the resources working times for 4 hours or
select a special 4 -hour/day calendar
Here are the results of the finnish jury :
- Start and finish dates change accordingly
- Gantt bar changes ok
- Duration remains 2 d!

MSP help states flatly :
If you have changed the working time in the project
calendar to more or fewer than 8 hours of working time per
day, tasks' durations won't match their Gantt bars.

Is there a fix available for this serious bug?
Should I create a calculated field and code to calculate
correct durations - and bind it to the scheduling engine ?
Maybe someone has done that...

Thanks !

 

[Dale Howard]

Erkki --

The behavior you are seeing in Microsoft Project is definitely not a bug.
The software is performing correctly. What you do not know about the
software is that the value in the Duration field is a calculated number,
based on the following formula:

Duration = Work/(Units x Hours Per Day)

The Hours Per Day value is found by clicking Tools - Options - Calendar. In
your situation, when you assigned a resource to work full-time to that 2-day
task, the following values were set in the formula:

Duration = 2 days
Work = 16 hours
Units = 100%
Hours Per Day = 8

When you changed the resource's calendar, the Duration was not recalculated
because the numbers are all the same as previously. The only difference was
the resource's individual working schedule at 4 hours per day, which
impacted the schedule of the task (as shown on the Gantt bars) only and not
the calculated Duration.

If you want the Duration formula to work correctly for your situation, set
the resource's calendar back to 8 hours per day, and then do the following:

1. Select the task in question
2. Click Window - Split
3. In the lower viewing pane (Task Form), change the Units value to 50% and
then click OK
4. Click Window - Remove Split

The Units value specifies the percentage of an average working day the
resource can commit to working on the task. By setting the Units value at
50%, that approximates a 4-hour working day. Hope this helps.