Actual Duration vs Scheduled Duration

Question

Actual Duration vs Scheduled Duration

Anonymous

Please clarify the use of the Actual Duration in the following situation:

Create a fixed unit, non-effort-driven task of 5d duration.
Assign 2 resources to at their max capacity: John (100%) and Tom (50%)

Project calculates:

a). Task Work = Duration * Units = 5d * 150% = 60h and

b). Individual Work for each resource: John : 40h, Tom 20h (See Fig.1) 3. Enter Actual Work and %Work Complete for each resource in Assignment Information dialog box as follows:

John: Actual Work = 60h, %Work Complete = 80%

Tom : Actual Work = 40h, %Work Complete = 50% 4. Project updates the scheduled Work, scheduled Duration and other values***(See Fig.2 )***

Based on this example please clarify the following:

a). What is the use of the Actual Duration value except for its part in calculations of %Complete = Actual Duration / Scheduled Duration (in this case it's 8.33d/ 20d = 42%)?

What confuses me is the fact that to me it makes sense that the task's Actual Duration should have been equal to the longest actual duration required for the two assigned resources to complete the work they completed to the status date. In this case the longest actual duration was incurred by Tom as Actual Duration (Tom) = Actual Work (Tom) / Units (Tom) = 40h/50%=40h/4h =10d while Actual Duration (John) = Actual Work (John) / Units (John) = 60h/100%=60h/8h =7.5d . These two durations are shown in the Task Usage View, that is, John actually worked for 7.5 days at the rate of 8h/day, and Tom worked for 10d at the rate of 4h/day.

So where in the Task Usage View to see the application of the task Actual Duration of 8.33d calculated by Project as Actual Duration = Actual Work / Total Units = (60h+40h) / 150% = 100h/12h = 8.33d ?

b). This question is partially based on the previous one. Why is the Scheduled (updated) task Duration is calculated as the longest duration for it's driving resource while it's not applied to calculations of the Actual task Duration?

Scheduled Duration (John) = Scheduled Work (John) / Units (John) = 75h/100%= 75h/8h = 9.38d

Scheduled Duration (Tom) = Scheduled Work (Tom) / Units (Tom) = 80h/50%= 80h/48h = 20d

As 20d is the longest duration for all assigned resources for the task, the 20d is the scheduled Duration for the task.

The same approach is not working for calculations of the Actual Duration as it was shown in the previous question as Actual Duration is calculated as task Actual Work divided by total Assigned Units, and the calculations of actual duration for the driving resource are not working in that case. Why does Project work this way?

Thank you,

Alex

Fig.1

Fig. 2

Locked Question. This question was migrated from the Microsoft Support Community. You can vote on whether it's helpful, but you can't add comments or replies or follow the question.

0 comments

2 answers

Answer 1

Task duration has always been the number of working days (or weeks etc.) required to complete the task. It is therefore unrelated to the number of resources or the amount of work they have.

Actual duration is the actual number of days of progress and is % complete * Duration.

In effect there is a duration for each assignment that is not available to display, but Duration is always the longest assignment duration.

Answer 2

That's a good question, if a rather long one. Here goes.

The first mistake in your description above is at step 2, part a)

"Task Work = Duration * Units = 5d * 150% = 60h"

It's not. Task Work is calculated as the sum of John's work and Tom's work.

Of course it comes out to be the same number, 40 + 20 = 60 hours, so 2 b) is correct, but 2 a) is not.

You 2 a) is not so much wrong, rather it is unnecessary.

I would say that the next mistake occurs at step 3 where you enter actual work and % work complete.

You have input too much data in one shot, and not considered what happens at each point.

Then you end up with a combination of results which are difficult to decipher because you can't connect cause and effect. Let's break it down, bit by bit.

First, forget about Tom.

When you input john's actual work as 60 hours, straight away you force MSP to increase the duration from 5 days to 7.5 days because there is nowhere inside the 5 days duration where the extra 20 hours will fit. It has to go somewhere.

Then you say that John's % work complete is 80%.

This forces MSP to recalculate the actual work to be 48 hours, and the remaining work to be 12 hours.

So, in effect, your input of 80% contradicts your previous input of actual work = 60 hours. You can't have it both ways, so which is it

What's next?

I am going to skip what you did with Tom at step 3, and ignore the result at step 4.

You ask "What is the use of the Actual Duration value except for its part in calculations of %Complete = Actual Duration / Scheduled Duration".

Well, actual duration is very useful because it is a fact, and there can't be any argument or difference of opinion about facts. Your definition of % complete is incorrect.

% complete is actual duration divided by total duration where total duration consists of two components which are actual duration + remaining duration.

I am going to skip, for now, everything below "What confuses me" because it is a rather jumbled up bunch of over-thinking. The problem is less complicated than you are making it. Step back a little and pay special attention to the definitions and vocabulary.

I suggest stop referring to "scheduled duration" and only use actual duration and remaining duration.

I suggest stop referring to "driving resource", since there really is no such thing.

Any help?

Share via

Actual Duration vs Scheduled Duration

2 answers