Group By Summary

Question

Hi All, 

I've got a small programme in MS Project 2010, and am using 'Group By' function to summarise various phases. 

The summary value for 'duration' is not calculating correctly. Is showing the maximum duration within the group, rather than the latest finish minus earliest start. The start and finish dates for the summary bar are showing correctly though. 

This problem is only in MSP2010, the duration appears to calculate properly in MSP2007. 

Any suggestions?

Thanks, 

Hugh.

Answer 1

hmcleay,

I haven't actually checked this out but it may be related to the addition of the manual scheduling mode in Project 2010. Instead of looking at the Duration field on the group summary line, look at the Scheduled Duration field.

Update: I just tried a sample file and indeed the above is true. The interesting thing is that if you first only display the Duration field and not the Scheduled Duration field, the group summary line Duration will indeed show the group task with the longest duration. However, if you then add the Scheduled Duration field, you will see the Duration value on the group summary line disappear. The Duration field on the group summary line will remain blank if you subsequently hide the Scheduled Duration field. Interesting.

Hope this helps.

John

Answer 2

Hugh,

Why would you think logic is involved? I mean, does it make "logical" sense to restructure the fields that users are familiar with and have used for years? Wait, let me answer that. No, it doesn't, but that's what the developers decided to do when the manual scheduling mode was introduced. To me, it would have made much more sense to leave the existing familiar fields alone and create a whole new set of fields for manual mode (e.g. Manual Duration, Manual Start, etc.).

I don't know why the group summary line Duration field shows only the span of the longest task in the group, but then there are lots of things in Project I can't explain. The trick is knowing (or finding out), the unknowns and then learn to work with them. Otherwise you will go crazy. Been there, didn't like it.

John

Answer 3

Thanks John, 

I've tried searching for the new definitions of these fields, but can't find anything.

IMO, there is no logical definition of 'duration' that would result in its 'group by' summary being calculated as the maximum duration of the group, rather than the latest finish minus earliest start.

I would expect that the calculation should be the same as how MSP calculates duration for an 'indented' summary, which it does correctly.

So, I still consider this to be more of a bug than an idiosyncrasy, hence my use of the term 'workaround'.

Anyway, thanks for your help on this topic. I will just be using 'scheduled duration' from now on.

Cheers,

Hugh.

Answer 4

Hugh,

You're welcome but I don't understand your last statement about a workaround being found. Using the Scheduled Duration field is not a workaround. It IS the solution.

When manual scheduling was added in Project 2010 several of the standard fields that were familiar to users got redefined. Not a smart move in my opinion but that's the way it is. So it's not a matter of the duration value being incorrect. The old familiar Duration field has been redefined. Surprise!

John

Answer 5

Thanks John!

Yes, using 'Scheduled Duration' does calculate the correct values. I think I'll use this field from now on.

Regarding the other behaviour that you noticed, I saw this also after adding the 'Scheduled Duration' field, but the reason the summary value disappears from the 'Duration' field is because MSP needs to calculate. If you recalculate (F3), both values appear, 'Scheduled Duration' being correct, 'Duration' being incorrect.

Workaround found! (but problem not fixed).

Cheers,

Hugh.