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Performance Factor (What do you use?)

12 replies [Last post]
Aytek AKTAŞ
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Dear planners;

 

As you know, for performance factor tracking we all use unit planned man hours. What i always do is; at the beginning of the project i forecast unit manhour for activity and i update it next forecast (in 3 months period). For exampe, for steel structure erection in forecast 1 i assumed 30 manhours per ton. Than i realized that actual at site is 32. i update it to 32 mh/t.

 

The question to planners is, do you use one man hour for one activity or you use more than one (i.e nov-april 40 mh/t, april to nov 30mh/t) ?

 

Regards,

Aytek AKTAS

Lead Planning Engineer

Enka Construction - Russia

Replies

Rafael,

I understood. In any case these artificial calendars shall be applied to resources, not to activities. Adjusting activity calendars is too hard and time consuming. This solution was applied as work around with the software people use. I would suggest not to change work time but play with resource workloads. In any case it is hard to implement and could create problems that you mentioned.

Best Regards,

Vladimir

Rafael Davila
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Vladimir,

Simon is fooling the true meaning of productivity by reducing available hours on his calendars. It will have the effect of delaying the activities but the schedule as shown will not be a true depiction of plan.

Here at the weekly meetings when shown a schedule displaying you have 4 hours to do a job when it really means 8 hours, at some point will create missunderstandings. Imagine scheduling work to start at noon (mid-day) and the proposed schedule display mid-mornig, in no time people will make jokes and very early the schedule will be discredited. At some times confusion will end up in chaos, unless nobody pays attention to the schedule details.

Here in case of a court claim it would be discredited again and ordered to show true planned work time. Then if done as others suggest for every required schedule a manual adjustment will follow.

Best regards,

Rafael

Hi Simon,

in your approach you shall know in advance which actiivities will be done on summer, and which will be done during Ramadan.

You select these activities manually and adjust your schedule with many iterations.

Since the deviations from the original schedule will take place you will need to adjust your schedule with each new iteration.

It is very time consuming if the schedule is large.

I don't know the size of your model but by my experience pipeline construction project models include more than 1000 activities per each 100km and at least 500 activities per month. Besides, only a part of certain activities will be planned for specific month. It is a lot of work.

Best Regards,

Vladimir

Rafael Davila
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It is not good scheduling practice to display other than your true plan and true working hours, making your calendar hours different to true work hours is misleading and can create serious issues in the case of a delay claim.

In addition, fooling the calendar does not solve other issues such as the need for a change in crew composition when doing work on different seasons, same as when doing work on the same activity during different same day shifts (night vs day, quiet hours vs hours where noise is allowed ....).

In order to be transparent you must display true plan.

If you know how to use your software and still you cannot make the real model as it should be then you are using the wrong tool and forever will be doing it wrong.

Simon Willson
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Hi Aytek,

I have just finished an oil pipeline programme in Iraq using Primavera P7. 

I created a spreadsheet of norms for pipeline welding based upon agreed international welding standards.  The project delivery stage was over summer where temperatures regularly hit 50 degrees plus!  I factored in an overhead of 40% (i.e. duration = 140% of the norm) to account for the harsh conditions. 

The delivery of the project was also over the holy period of Ramadan.  In addition to the 40% overhead, I used an activity calendar to model the period of Ramadan and ratcheted the working time down to 50%.  This worked very well and proved to be very accurate.  The same concept would apply for your seasonal variation.  The calendar was assigned to the task rather than the specific resource. 

Hope this helps.

 

Regards

 

Simon

mimoune djouallah
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Aytek

 

Hmm interesting question, actually we use the same productivity for the same activity all the months of year although we know for example that the planned productivity should be less in Ramadan. The reason we are lazy ;) and we do like linear distribution curve. But yes we update this productivity using the actual performance in the site, the morality is to have more realistic forecast.

 

But if you are brave enough, you can always model special curve to be applied for the activities that fall in that special period (winter, summer or Ramadan).

 

Just as an example; p6 can model this using future bucket, it means you can input manually the planned quantities by period.

 

Good luck

Rafael Davila
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Activity is the same, it is a matter of resource allocation on each Shift that represent a season. If you split the activity as the job progress the two splits will move and therefore in other to keep them aligned with the seasons you will have to manually adjust each. Insane if hundreds of activities and not to mention the effect of resource leveling on each split.

If you have a 4000 activities job an 50% of the non-winter activities can shift to winter and 50% of the winter activities might fall in summer it means that at least 2000 will have to be spliced. Are you to manually adjust the extra 2000 splits every time you update your schedule? Get real.

Remember that depending on where the split occurs you will have unlimited mumbler of possible split distribution, resource allocation and split durations according to seasonal productivity.

If you know how to use your software and still you cannot make the real model as it should be then you are using the wrong tool and forever will be doing it wrong.

http://www.youtube.com/watch?v=ouuUZW2kHC0

Alessandro Gebbia
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Hi Aytek, your question is very interesting and I have been involved in my life in several cases like this. I would suggest you the following but i don't know how big is your project in terms of hours and resources:

1) In my opinion manhours are standard so you cant touch it unless you apply what we call "productivity factor". Infact the seasonal effect is mainly a matter of productivity. For istance 1.20 - 1.25 could be a valid parameter to transform standard mhs into a more effective mhs during warm season. In winter it increases so 1.40-1.45 should put you on a safe side. Of course this point is for phisical progress and for resource dimensioning.

2) I think one way to solve the problem (in case winter is very hard) is to consider the splitting of the activities. Why this, if winter is very hard you cant consider it "normal" or "standard". In such a case the "standard" mhrs cannot apply and you are forced to evaluate the possibility to consider a new standard only for winter time.

3) We need to use two different standards as far as mhrs are concerned and this imply the splitting of the activities. In this case the Activity X is splitted in Activity X1 (i.e. from spring to fall) and X2 (i.e. winter). Both fragmented activities must be connected by a FS link. In certain areas of the world winter season could not be considered as a "cold" season only but a real bottleneck. In this case warm season is one story and the cold season is another story.

4) Ofcourse it depends on how important is the winter impact for your project. Low impact could bring you to consider to manouvre resorses in an old fashion way, hard impact should bring to consider the same as a new story. I would even think to place a milestone or a flag in between.

5) I always took my decisions along this path and at the end I always been able to sleep at night.

Ofcourse this is a simple opinion, i dont know anything about your project parameters, so keep it as a contribution in order to be less software-dependent but more project oriented.

Alessandro Gebbia
PCM - Petrochemical Industry Consultant - Italy

Rafael Davila
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Shift Calendars

Note that during the winter period resource B is not scheduled to work on Mondays nor Tuesdays, for whatever reason, while resource C works only on Mondays.

Mike Testro
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Hi Aytek

If you assign more than 1 resource to a task then you have to decide which one is going to be the driving resource to determine the duration.

Rafael is quite correct in using calendars to determine seasonal variations as these can be adjusted to record actual conditions.

It is important however that the same resource calendar is applied to the task otherwise chaos reigns.

Best regards

Mike Testro

Rafael Davila
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Posts: 4832

Aytek,

I believe you are correct with the point that seasonal changes must be considered in your modeling if relevant. The problem is that usually it is not as easy as planning using a simple factor adjustment, crew productivities and assignments are more complex.

If your activities are affected by seasons due to climate or seasonal resource availability you shall take this into account within your model. Your model shall be able to correctly model shift work and changes in crew composition and productivities as the activities move through the calendar. Adjusting hundreds of activities manually every time the schedule is updated would be impractical.

Seasons Scheduling

www.youtube.com/watch?v=rfl99TMXoqw

Best regards, Rafael

prashant singh
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Hi,

 

yes, you can use one man hour for one activity or you can use more than one. As you asked above, when you are update your resource profile after 3 month, you are updating the Estimate To Complete Hours which is again depend on activity.

 

Cheers !

 

Praz