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Disabling specific resource assigments ON and OFF

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Rafael Davila
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I would like to know if there is a simple way to disable on and off specific resource assignments without making changes to the assignment so I can easily get them back.  At the moment I can easily disable resource leveling across the board very easily but at times I would like to be at the individual assignment.

Needless to say this is intended for temporary calculations as it will allow over allocations I can latter on handle individually. It will allow me resource level an activity without disabling all assignments. Also will allow me to create scripts that disable and enable back such assignments.

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Rafael Davila
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Steve,

The following article might be of interest.

Understanding the Occurrence of Two Total Floats in One Activity and Schedule Crashing Approaches for That Situation.

  • 1.2. Observation
  • When multiple relationships or a lag/lead time is used in a CPM diagram a situation can arise where there are two different total floats for an activity, start total float (STF) and finish total float (FTF). STF is the amount of delay at the beginning of the activity whereas FTF is the amount of delay at the end of the activity without delaying the whole project. When this happens, either the start or fin-ish dates of the activity, whichever is critical, must be followed because the critical path follows zero total floats. It affects how a project can be managed based on where the critical path follows.
www.scirp.org/journal/PaperInformation.aspx?PaperID=36837#.VMi_Y2jF9yU 

Best Regards,

Rafael

Steve, imagine that a critical activity has calendar exception, like non-working period in Winter, and preceding activity starts on Autumn and finishes on Winter. This preceding activity is not critical but if it finishes earlier succeeding critical activity may be done before Winter.

This example reveals new problem: Drag may have limits from both sides: it makes sense to shorten an activity not less than ... 

Stephen Devaux
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Rafael, this is one of the amazing things about Spider Project. They really do have an unfair advantage over competition -- they have someone who really understands project management! And they react promptly to perceived needs.

Vladimir wrote: "Steve, there are cases when  non-critical activities still have DRAGs when multiple calendars are used."

Vladimir, Iam not doubting uou -- I just don't quite understand. Is it that the calendar can indirectly delay the end of a project despite not being on the longest path because it delays something else that then delays the longest path?

Fraternally in project management,

Steve the Bajan

www.TotalProjectControl.com 

Rafael Davila
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PERFECT!

WORKs AS EXPECTED WITH QUANTITY AS WELL AS WITH WORKLOAD AND NOTHING IS LOST.

Rafael, download the new version. Your request is done.

Steve, there are cases when  non-critical activities still have DRAGs when multiple calendars are used.

Rafael Davila
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Take a look at the following figures.

Top one: Shows 3 non-idle individual assignments and a project duration of 13.

Next one: Shows resource A on activity 1 idle and a project duration of 13. This assignment is not critical and is not delaying project duration. Resource Assignment DRAG equal 0.

Next one: Shows resource B on activity 1 idle and a project duration 10. Resource Assignment DRAG equal 3.

Bottom one: Shows zero duration for activity 1 and a project duration of 10. Activity DRAG equals 3.

This example shows how individual assignments might have different DRAG. To my eyes it fails to disclose Activity i is critical by its finish node if just looking at the red color of the bar, both activities are critical.  It is not a good example of critical resource assignments on non critical activities. I will look for a better example to show how resource assignments not on critical path activities can delay project completion. I started with the example on the reference as the easier way to show how different assignments on same activity can have different DRAG.

Maybe the issue is on the definition of critical activities, maybe both of us define critical chain activities those with either Start or Finish float equal to zero while other references only consider the Start Total Float.

Assignment Floats photo AssignementFloats_zpsd7a48840_1.jpg

You can tweak the color of the bar to make it Red if either Finish or Start Float are 0, but a bit cumbersome. 

Stephen Devaux
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Hi, Rafael.

I have to wonder precisely what is meant by: "(R)esource assignments may be critical even on non-critical activities." If they make the path they are on on the resource schedule into the longest (critical) path. then I agree "it follows such resource assignments will have DRAG and also the non-critical activities to which they are assigned."

But is that what it means?

Drag is only on the critical path because that is what delays project completion. A resource bottleneck that is NOT on the critical path of the CPM schedule can have drag IF it delays a path on the resource schedule so much that it becomes the longest path on the resource schedule path.

O course, a single resource bottleneck could delay both the longest AND the second longest paths. Would its drag then be equal to the sum of those delays? The question is really for you as a user -- what information would be of most use to you?

Fraternally in project management,

Steve the Bajan

Rafael Davila
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From: http://www.spiderproject.ru/library/pmie01_rcp.pdf 

 

Assignment Float photo CriticalResourceAssignments_zps2cf0f015_1.jpg

If resource assignments may be critical even on non-critical activities it follows such resource assignments will have DRAG and also the non-critical activities to which they are assigned.

Best Regards,

Rafael

Stephen Devaux
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Rafael wrote: "Do not take everything I am saying as correct, as for me this are new ideas,..."

New for you, new for the world! Yes, I have thought about these things for many years -- but even so, my thoughts are by no means fully formed. Things I think may be true may turn out not to be, and others may conceive ideas for assessing and measuring resource-leveled drag that are much more useful than my ideas.

Some thoughts:

The difference between the CPM project duration and the resource-leveled duration is a difference that can be isolated to the lack of availability of specific resources on specific activities at specific times. This is valuable to the user because it allows the measurement of the impact of the specific resource unavailability.

If the delay in project duration is monetized (i.e., resource availaility drag cost), that will "cap" the amount that it is worth paying to make that resource availability drag go away. Unlike CPM drag, where the nature of the work is usually what causes the delayand which is often hard to change without altering newtonian physics, resource avialibility drag is very susceptible to alleviation through more money for resources.

It is still only the longest path on the resource-leveled critical path that has drag. For instance, if Activity X which had CPM float of 10D now has a resource whose unavailability delays it by 15D, it would have 5D of drag. But NOT if parallel Activity Y has a resource whose unavailability delays the project by 8D! In that case, Activity Y (and the delaying reosurce bottleneck) would have drag of 3D and Activity X (and its resources) have TF of 3D and no drag -- because even though the resource unavialibility on X is delaying Activity X (and its path) by 15D, it's NOT the factor that is determining the end of the project (and probably reducing expected project profit).

Addressing and obviating the delay caused on Activity X will not affect the project duration. And that's what drag calculation should do -- help the user identify exactly what items need to be addressed to make the project more profitable.

Does this make any sense to you, Rafael? I am eager to hear other thoughts.

I am also eager to hear how specific software actions like removing resource assignments could help implement this or other decision-making, but you'd probably need to hold my hand as you lead me through that forest.

I do continue to believe, however, that Spider's ability now to do this sort of thing is, to quote Joe Biden on another subject, "a BIG ******* DEAL!"

Fraternally in project management,

Steve the Bajan     

Rafael Davila
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Idle resources will not drive activity duration, if activity duration is driven by resources only active or non-idle resources will be considered and this might increase/decrease activity duration. If a Duration Type activity no resources will drive activity duration as it will be fixed, Productivity Type activities are different.

Yes I believe it would allow Spider to manually compute what I would call Resource Assignment DRAG but maybe Vladimir can find more efficient ways as such computations might slow schedule calculations. 

If you disable two out of three resources then it might be the combined effect is not defined by individual assignments and this is where I believe the idea could shine.  

I suppose if it is of interest what resources are critical, and it might happen they occur in non-critical activities, then how much is the contribution (of such resource assignment) to total job duration is of interest (DRAG).

It is curious that under resource driven durations that making idle such assignment the total job duration might increase creating the possibility of a negative resource assignment DRAG result. If all resources are made idle then the duration of resource driven will be infinite and schedule calculation will be stopped.

I also believe that under Monte Carlo all unnecessary calculations that increase Monte Carlo running time and are unnecessary shall be automatically disabled for Monte Carlo runs while for regular deterministic schedule runs it shall be kept as an option that can be toggled ON/OFF, as it is now.

Do not take everything I am saying as correct, as for me this are new ideas, just let me know if you disagree.

Stephen Devaux
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Rafael, I think you may be on to something that, combined with drag and drag cost, is super interesting to me-- but I am not sure I am comprehending properly. Can you help me?

When you say: "...disable resource leveling... at the individual assignment," do you mean that the activity's duration (and perhaps drag) would then NOT be resource-driven level but at the CPM-defined duration?

Because if so, the knid of "automated" process you describe would, I think, be VERY interesting. If the software toggled on and off each activity's resource assignment (and thus back and forth between its resource-driven and CPM duration), doing it, say, in order of least float tomost float, wouldn't it allow Spider to compute the critical path drag of each resource-leveled assignment, and thus the resource availability drag of both the resource under-availability and of the activity itself? If so, that seems very useful to me!

Rafael, again my understanding of what you are asking may be way off. If so, please just shut me up. But if it's not, I think you are onto some very interesting functionality.

Fraternally in project management,

Steve the Bajan

Rafael Davila
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I figured out you can force an assignment to be idle by making workload equal to 0 plus variable and minimal workload equal to 0 and then with the use of user defined fields and a few formulas you can restore the three values. It would be easier if this procedure is automated.

What if an option filed "Make Idle" Yes/NO is available and when Yes the software will calculate assignment as if workload is 0,  with variable workload assignment with min set to 0.  Under workload the disabled value would be shown with an asterisk as to indicate it is forced to be idle, the same would be for min workload and variable q&w assignment fields so you have full visibility on disabled settings.

Of course the question is if this added functionality is worth it or not.

Idle Assignments photo IdleAssignments_zps8308b3e3-1.jpg

Rafael Davila
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....

Rafael Davila
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Vladimir,

As I said I am aware of the capability of Reference Books a functionality I consider most powerful, not difficult especially if standard reference books, but it takes more time than simply changing workload assignment to 0 and restoring.

You said, "I think that it makes sense to change this and permit such activities to be executed in parallel."

I believe it might give me what I am looking in a very simple way, easier to restore workload than all parameters, it seems you got my communication at 100%.

Best Regards,

Rafael

Rafael,

assignment parameters are not lost if resource assignment reference-book was created. You may make any changes and create any number of what if versions and then apply this reference-book and restore all initial assignments.

You may select if to level any specific resource but not specific assignment. I am afraid that such option for every assignment may be confusing. People may forget to switch on or off some assignments and finding this error in thousands of projectresource assignments is not easy.

Now if resource is not available an activity that requires this resource is delayed even if the required quantity is zero. I think that it makes sense to change this and permit such activities to be executed in parallel.

Rafael Davila
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Vladimir,

If I assign a workload of 0 it will still delay the activity after resource leveling.

Workoad 0 photo Workload0_zps3380eebd-1.jpg

I am looking to be able to temporarily set quantity equal 0 to a specific assignment and being able to recover whatever quantity it was along with all other assignment parameters.  I would like to see all disabled parameters including a parameter that flags the assignment is disabled, similar to links parameter "consider in scheduling", perhaps "consider in leveling", I want to be able be able to toggle on and off specific assignments using simple scripts.

In this way I can see what effect on the schedule will have the deletion of the assignment without erasing the data as if I change the quantity to 0 the assignment parameters are lost.

Best Regards,

Rafael

Rafael,

I don't understand what are you looking for. Disabling individual assignments can be very different. Adding or removing resources from resource crews may be done in multi-resource table, making resource workload equal to zero you actually define that this resource is not used though assigned. Making resource assignment reference-book you may make any changes and then restore original assignments.

Regards,

Vladimir

Stephen Devaux
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Rafael, that's it exaclty! I talk about this in my book.

I am really curious how it will turn out for you if you can do this.

Fraternally in project management,

Steve the bajan

Rafael Davila
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Steve,

To be honest I was not thinking about it but it might provide functionality to calculate Resource Assignment DRAG, different from resource leveled activity DRAG.  I like your suggestion.

At the moment Spider gives you float values on activity lines as well as on resource assignment lines but DRAG only on activity lines. It might be some assignments are critical while the activity per-se is not, a concept exposed by Vladimir in some of his readings.  It is possible Spider is the only software that can calculate resource assignment float.

Best Regards,

Rafael

Stephen Devaux
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Rafael wrote: "Needless to say this is intended for temporary calculations as it will allow over allocations I can latter on handle individually."

Rafael, are you doing this while computing resource schedule drag? it would seem to me that, if this can be done, it would be incredibly useful.

Fraternally in project management,

Steve the Bajan

Rafael Davila
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Bodgan,

Resource assignments can be complex, it is not just about quantities but productivity, workloads and quantity that can be fixed or partial. Perhaps reference books can do it but I am looking for an easy and fail safe approach.

In a similar way links can be complicated but there is an option for use in scheduling or not.

For complex what if I use several file versions but still this is not what I am looking, I am looking something that can be toggled on and off using scripts in a way similar to what you exposed but taking care of all parameters.

Rafael

Bogdan Leonte
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Rafael,

off the top of my head try the following:
1. Create a user field entitled "Original Resource Quantity" and a formulas 1. ORQ = Number & another 2. Number = ORQ
2. In the Gantt Options check the "Show idle assignments";
3. Apply the first formula and then make the quantity of the assignments you want equal to 0, then reschedule.
4. Compare the results and use the second formula to "Undo" all the changes to the resource assignments Quantiy property.

Hope this walkaround works for you.

Regards,
Bogdan

Rafael Davila
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I understand that activities whose duration is dependant on resource production might be in conflict and maybe such assignments shall always be on.