Difference between "duration" and "effort"?

[abusch]

Sorry for my ignorance -- this is probably project management-specific language -- but could anybody explain to me what the difference between "duration" of a task and "effort" for it is?

I note that the two sometimes differ, and there seems to be a correlation with the level of completion and changes in the schedule, but so far I don't quite see how they co-vary...

[mattao]

As far as I know:

effort is the working time necessary to do something:

Exemple: to draw this house plans it will take 40 hours work.

Duration is the time it will take.

If two people make their efforts to do this task it will take them 20 hours ( duration ) to do this 40 hours ( effort ) task.

(You will note that two people working together on a task rarely succeed in dividing is execution time by two but....)

Hope I helped.

[Lizard]

mattao's correct. Also, if one person is assigned at 50% to a task with effort 10 hours, it's going to take him 20 hours to complete. (Think of a lazy person drawing the house plans, or someone who keeps getting interrupted by other responsibilities.)

[LkwdBrian]

although, according to my project management training, you really should only assign one task to one person.. if the task is too big for one person you should break it down into smaller tasks that can each be done by one person.. this makes managing the project much easier and makes things go more smoothly... for what it's worth... :)

[ukko]

It really depends on the project, does it not? If I am painting a house or mowing lawns it is easy to add people and not have to split tasks. Now that will not hold for coding tasks. But hey my test case I am using OmniPlan on is a basement remodel, so I am biased.