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Calculate remaining units per time from crew sizes

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Dennis Hanks
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Working on a conceptual construction schedule where I have the total hours and have guessed at crew sizes for the various crafts.  Right now, to get durations I have to change the default remaining units per time by multiplying it by the assumed crew size.  What I would like to do is have P6 do this for me, but I cannot get Global Change to cooperate.  I want to have an 'Activity Resource Assignment' UDF (crew size) multiply it by the default day in hours/day to get the remaining units/day and do it all in the 'Resources tab'.  It seems simple enough, so I am overlooking something.

I expect to go through this exercise several times with different days and crew sizes, so anything to minimize the math will be beneficial.  I would like to be able to easily change the variable - crew size - for the various crafts using the 'resources tab' and see the results graphically (in P6).

Any thoughts appreciated.  Thanks.

Replies

Zoltan Palffy
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change the activity type to Resource depanedent and change the duration type to fixed units/time 

Rafael Davila
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As previously said the goal is to be able to vary crew size and immediately see the impact on the activity duration and on the resource leveled schedule as a whole.

  • As you can see in the previous example you can change productivity only and this will result in changed activity duration as well effort or resource hours [units] without any change in the resource quantity. 

    On the other hand if you change resource quantity the activity duration will change without any change in total effort, it is just that with less resources same effort it will take more time to do the same volume of work.

  • It shall be easy and transparent.
  • There should be an easier way to do so in your software! 
  • So simple, so easy.
Rafael Davila
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Please be reminded that MSP nor P6 have a field for crew size, they just use effort and attempt to level resources using effort, and this might create unfeasible schedules.  In this software you will never update resource quantity but effort; you will never update available resource quantity but available effort which can be related by complex relationships under partial workloads.

Cpm schedules - resource quantities and workloads from Rafael Davila

Volume of work from Rafael Davila
Michael King
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4809
capture1.png

Michael King
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...

Michael King
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Hey Dennis,

 

I realize this is a very late response, almsot 6 years haha, but I have determined a way to show what you need through 2 global changes. The first one is the change the crew size, use the below 1st GB. Then use create a UDF field named crew size, and a user defined field named Remaining Units/Time and use the next global change.

 

4807
capture.png

Jessie Ramos
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Rafael Davila
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Well this is as far as I can go without having P6, still I believe this is such a basic need it shall be available without the need of any UDF and global changes. It shall be easy and transparent.

http://youtu.be/4RwlszpYYq4

Good luck,

Rafael

Dennis Hanks
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No, all necessary fields are available, except crew size, in the 'resource tab'.  Crew size does exist when viewing the project under "Resource Assignments".  But if you create a UDF called 'crew size', you cannot use it to do the math of multiplying crew size by default units/time to get a remaining units/time to determine the duration.  At least, I have not been able to do so.

The goal is to be able to vary crew size and immediately see the impact on the activity duration.

Rafael Davila
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Do you mean Remaining Units is not an available field?

Remaining Units / time = Remaining Units / Remaining Duration

Even Units/Time shall be an available field. Perhaps because P6 do not handle these at the resource level you are not able to find them under the resource tab but maybe, ???, you can find them under the activity table as available fields.

Dennis Hanks
User offline. Last seen 8 years 37 weeks ago. Offline
Joined: 17 Apr 2007
Posts: 310

Rafael;

Fixed units is the key.  The estimated remaining manhours should account for all expected productivity factors, so the only real variable is crew size when determining activity duration.  Currently P6 provides a default units/time (hours/day) that has to be manually manipulated to reflect crew size (number of men X default units/time).

What I want to do is be able to use 'crew size' as a UDF to determine the remaining units/time and do it on a more or less real time basis.

Again, thanks for your suggestions.

Rafael Davila
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Well I do not know well P6, I used P3e years ago, but what you are doing makes so much sense that what you are asking shall exist in some easy way.

Best regards,

Rafael

Dennis Hanks
User offline. Last seen 8 years 37 weeks ago. Offline
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Rafael;

Thanks for the reply.  The math is not the problem (hours are already determined).  Getting Primavera to do the math is.  Remember this is a "conceptual, high-level schedule", I do not need the 'granularity' you suggest.

Looking for a technique that will allow realtime calculation of duration given estimated hours and crew size.  Right now this can all be done in Excel, but I was hoping for something that would let me do this in the P6 'resource tab' and then F9 or run Global Change.

Again, thanks.

Rafael Davila
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Dennis,

This is an everyday issue you shall be able to handle easily, it usually a bit "less easy" because of the fact many individual resources do not have same productivity. For example a 20-cm truck and a 30-cm truck have different earth moving capabilities. You shall be able to model different resources with different productivity as same skill, and depending on availability the software will adjust activity duration. Same goes for a masonry crew with different composition, a few masons versus a few mason apprentices with lower productivity.

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If your software cannot handle this issue directly and transparently only then you shall consider alternate ways.

No matter how you do it it is important to keep the relation between resource assignment and remaining duration, it shall be automatic and transparent otherwise Murphy will show up at the worst moment.

I don't use P6 but believe using multiple UDFs and multiple Global Changes in this particular case is calling for trouble if you do not keep a record of remaining duration and resource loading values before adjustments are performed, this mean a few extra global changes on UDFs. Kind of compliicated.

Best regards,

Rafael