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Resource Level Activity with Multiple Resources

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Oran O Leary
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Hi,

 

Is there a way to automatically level resources if I have more that one resource assigned to an activity? Say I have an activity 100 days long and the second resource assigned is only 10 days long. By default P6 makes this second resource start at the beginning of the activity. This does not change when I resource level. Ideally I would like this 10 day resource to move around within the 100 day activity until it finds its optimum start/finish dates within the 100 days to allow for more compact resource leveling with other similar resources in different activities. I can change the dates manually to get what I want but for +500 activities this is not really practical. Any thoughts? Cheers, ool.

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Rafael Davila
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For the schedule I illustrated before I used two approaches, in this particular case both yielding similar schedules and resource floats.  While the model preparation essentially required the same resource loading data but on different activities the number of logic links duplicated on the approach using individual activities.

Only twice because for simplification and to save some space on the figures I limited the number of different teams working on an activity at different shifts.  After initial design it is possible electrical, plumbing, site, structural and architectural designers can work independently of each other.  This makes it easier for the preparation of the schedule and in case of changes also makes it easier to change the logic.

I find it easy to determine when to use shifts on same activity and when not to. I do not see why not using shifts on same activity even if hours/work is fixed when the logic to outside activities is the same and there are no internal links among the resource assignments. 

If instead of 1 activity and six links you use 3 activities for 3 independent teams and 18 links total you got a lot of redundancy, two redundant activities and 12 redundant links because it all could be modeled if using a single activity.  I have a tolerance for some redundancy but not for too much of it.

It is possible that at some stage on the site design you will have, architect, site civil designer, electrical designer, plumbing designer, and a couple of draftsmen, at times working alone [independent of each other], at times working in small different groups [on different teams], at times all working together [as a single team].  If using one activity per team this approach will exponentially increase number of activities and links.

Resource Teams photo Resource Teams_zpskrqbpnch.jpg

http://www.planningplanet.com/forums/asta-powerproject/576477/asta-pp-re...

It all depends on the Client maturity.

But we moved away from the discussion topic.

We can discuss details in the separate thread preferably in Spider Project forum.

Rafael Davila
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I would use the same schedule unless by necessity a Ghost Schedule is necessary to include activities still rejected.

I would update the Schedule/Ghost on a weekly basis, say versions 14, 15, 16 and 17 if four week endings within the month (can be 5).  We would update the additional activities still rejected by the client if this is his approach.

By the end of month I would save last month update as either 17 or 18 if a new DD update is used. This schedule would have the additional activities necessary for our management that are being rejected if this is the client approach. I would save under a separate set to keep monthly updates, say version 4 of monthly updates, would delete the activities the client do not want to see, but all coming essentially from the same schedule, essentially same number of activities with same durations, whatever we determined were appropriate. This I would do for my own jobs as when when I was a project engineer before becoming PM.

Now it is more common a monthly update and use of the fly by night scheduler because each client wants different software to the one the contractor uses. The contractor would schedule one month look ahead using Excel.  The fly-by-night scheduler moving to south, PM moving in any other direction because usually the software mandated cannot follow the way the Contractor is to manage his job due to poor resource planning capabilities that cannot do the basics as variable quantity resource planning. 

If the owner do not want to see all the details he can take a look at another WBS level report, an usual requirement, they usually insist on having all the details on record, they ask for both levels of detailing.

The requirement to limit activity durations in construction schedules is nothing new, as a matter of fact it is a common practice that frequently creates confrontation with some of us that believe in automatic resource leveling. A convenient approach for those who prefer manual resource leveling that might force the scheduler to set aside the automatic resource leveling and use manual leveling.

Rafael,

Let's consider simple example - construction of some building that consists of floors (let's suppose that building each floor takes two weeks), on each floor there will be walls, columns, floors, staircases and elevator shafts, for building each different works will be planned (reinforcement, concreting, installation and removal of frames, etc.), resources assigned, etc.

If the Client collects project reports and analyzes schedule status once in a month he does not need these details. Maybe he will be satisfied with the schedule where each floor is represented by one activity with SS and FF links with lags to the next floor.

These schedules are different not only by the level of details but also by durations, costs and even resources. Contractor plans the work of every crew, the client is interested in overall labor quantity and hours.

Rafael Davila
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The schedule granularity may depend on required update periods and management requirements.

  • I do not agree schedule granularity shall be dictated by updates periods, it should be whatever it is necessary to make a good model, in my case to make a good automatic resource leveling model, fixing activity duration might preclude a better model.

If the schedule is high level and intended for monthly updates it requires less details if to compare with the schedule that shall be updated and analyzed daily.

If the decision on more precise management is taken then the schedule shall be adjusted to help with daily (weekly) decision making instead of monthly analysis. It can be done using rolling wave technique.

  • As I see it the level of detail for each activity, no matter the updating period shall not be dictated by the updating period but by how the modeling works.  If CPM with no automatic resource leveling it would not matter but this is not what I consider good practice as manual resource leveling is not a pragmatic approach on my schedules.

As we both know contract schedule and contractor schedule are not the same.

  • As we both know, contract schedule, over target schedule, schedule updates and contractor schedules are not necessarily the same.  Usually contractor schedule update is an over target schedule that makes sense to be very similar to the others, necessary when client rejects true plan because they fear this will represent a change in contractual conditions when only Contractual Baselines do. 
  • If for every one month duration activity the contractor schedule must be adjusted to four activities as to limit the activity durations to one week updating both schedules will become a nightmare.  Our approach is completely different we prefer to prepare similar schedule models with minor differences to allow for planning on activities rejected by the client when he insists on doing so, increasing the activity count by four and at the same time losing the continuity of the contiguous model we do not like.

The schedule granularity may depend on required update periods and management requirements.

If the schedule is high level and intended for monthly updates it requires less details if to compare with the schedule that shall be updated and analyzed daily.

If the decision on more precise management is taken then the schedule shall be adjusted to help with daily (weekly) decision making instead of monthly analysis. It can be done using rolling wave technique.

As we both know contract schedule and contractor schedule are not the same.

Rafael Davila
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Some of us do not limit our updates to 0% or 100% rule even if it is hard to estimate remaining work/hours to be done some of us prefer to estimate remaining work/hours and if necessary adjust the schedule budget as some of us believe planning is a dynamic thing.

I do not believe our design office common practice is to use CPM Software but they make plans, mostly manual, and update them, the scope might not change but the resource planning [assignments] do.

When the GPCCAR says "ensure" it does not looks like optional, more likely as a mandate across the board.

Some of us believe the CPM model shall capture contiguous work within a single activity unless it is not because there are necessary interruptions to improve the model.  Some of us do not believe on arbitrary splits of the activity and believe updating frequency is not a good reason to put upper or lower limits on the duration of activities.  Arbitrary splitting of activities might be damaging to the automatic resource leveling.

Do you mean that if a schedule to be updated monthly is changed to be updated weekly is no longer valid?  What if the required update is monthly but the contractor wants a more dynamic updating for his own use?

Rafael,

if an activity has certain physical volume that can be easily measured then project planner may rely on reported actual data and estimates of remaining duration.

If an activity performance is measured in mythical percents then remember Murphy's Law: The first 90% of a project takes 90% of the time, the last 10% takes the other 90% of the time.

So if at weekly meetings people report on percents that were done instead of stating that some activities were finished and others started project manager just does not have reliable information on project status.

That is why we recommend to make most activity durations compatible with the periods of project performance analysis. An exceptions of course may and will exist and this rule is not strict for productivity type activities.

 

Rafael Davila
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Do not interpret GPCCAR literally, in some occasions there are more exceptions than the rule this draft has.

07.6.1 INTRODUCTION

 

Activity durations may be assigned a preliminary estimate when duration does not depend on assigned resources or may be calculated based on assigned resource productivity and activity volume (amount) of work to be done.

As explained above, ensure that activity durations match the planned period of the project reporting; for example, if the project requires you to analyze project performance weekly – activity durations should ideally not exceed one week.

An activity duration shall be what it is and such rules are nuts.  In linear schedules such as the installation of a trunk line activities might take several weeks or a bit over a month.  I do not believe many months because there are usually intermediate points that call for a split.  Even is the schedule is updated weekly it does not make sense for all activities at what the GPCCAR calls level 5 be limited to updating periods, this is wrong.  When you artificially split activities they the chunks are no longer contiguous and resource leveling might yield undesired results unless you perform manual resource leveling.

The same goes with design schedules, our current practice is to have intermediate approval/agreement points that require individual activities to be split.  The schedule is updated at the design office perhaps weekly as to re-align assignments but activities are not reduced to weeks, that would be nuts.

I would never use GPCCAR "as-is".

Johannes Vandenberg
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Hi Oran

Your question.

Is there a way to automatically level resources if I have more than one resource assigned to an activity?

Yes, you can level resources in P6. I would not use the word automatic. There is little automatic on effective resource leveling; it requires significant expertise, experience and skills and hard work to do this.

Module 07-05 Assigning resources to all activities of our GPCCAR explains this in great detail. Item 18 of Para 07.5.4 outputs sums it all up in one sentence “Resource leveling occurs only on detail schedules that include detailed resource estimates supported by historical data and sound estimating methodologies.”

Resource leveling on activities with a duration of 100 days is not very efficient. 

I would recommend studying the GPCCAR as this is a base for better project control

Regards Johannes

Rashid Iqbal
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Hi,

What i know that P6 can't be/should not be used to model a process i.e. Calculating the number of Transit mixer required for a batching plant or to calculate the number of trucks required per shovel for a haul distance etc. This kind of resource modelling falls under the simulation category and so a software should be used that is escpcially designed to do so (probalistic durations instead of deterministic).

 

 

Regards

Rashid

Rafael Davila
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Vladimir,

If you fix  the duration of all teams then total teams duration within the activity will be fixed keeping its original value.  The case where the start of earliest activity and finish of latest activity gets too far away is analogous to a single activity being stretched by the resource leveling.

When some lag among the assignments is required it makes sense to model the requirement using different activities as to keep the relationship among the resources instead of a simple start lag that will not make it. 

The point is that what Oran asked is feasible alternate model if using Spider Project but not if using P6.  If using P6 the only alternative would be using separate activities.

The issue on shift work becomes more complicated when the total work hours/volume is fixed but different teams have no fixed hours/volume, teams will work on the activity as soon as available and work will finish when total work hours/volume are realized.  A similar situation and perhaps more real if using different production rates among the available resources to contribute to the activity. This somewhat different case you cannot model if using separate activities, this you cannot model in any way if using P6, this you can model if using Spider Project.

Best Regards,

Rafael

Rafael,

assigning teams we can get the situation that different teams will work at different time and activity duration will exceed its original value.

Besides, P6 cannot model independent teams, so the only solution that I can imagine is creating several activities instead of one.

Rafael Davila
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But what about different teams working on the same activity, each a fixed amount of hours, like it happens in design firms?  Some design activities will require different teams, not necessarily all working at the same time as if different shifts, but the activity is performed as a whole by all the teams.

I believe that if you cannot model such scenario then you cannot model SHIFT WORK ON SAME ACTIVITY. I do not believe P6 can.

Fixed for Teams photo Fixed for Teams_zps6zufy2za.jpg

Hi Oran,

it looks like the second resource will do another job that requires only 10 days and shall finish before the finish of 100 days activity.

Can you describe real life situation that requires such model?