Good day all.
For many years now I have tried to get a very specific answer to a resource and cost related issue with Primavera from all kinds of industry experts, training experts and Oracle themselves, all to no avail.
To pain the picture, what would be ideal is that activities could carry detailed resources of all types with their associated costs and have no relevance to a performance or productivity assumption, as we all know, the assumption will very rarely be what actualizes.
Simple example.
Activity - Build Steel Structure
Steel structure has a BOQ of 1000 tonnes of steel, at say $10 per tonne (material resource)
We can assume we need a crane at say $50 per hour (non-labor resource)
1 steel erector at say $5 per hour (labor resource)
1 supervisor at say $15 per hour (labor resource)
Assuming this estimate duration is 20 days, we create the activity (task/resource dependent) with the resources above assigned to them with their relevant costs and quantities
UoMQtyRateDays SteelMaterialtonnes1000 $ 10.00n/a $ 10,000.00Steel ErectorLaborper hour1 $ 5.0020 $ 800.00SupervisorLaborper hour1 $ 15.0020 $ 2,400.00CraneNon-Laborper hour1 $ 50.0020 $ 8,000.00 $ 21,200.00
So assumptions on costs as above.. Activity is loaded with these 4 resources.
Steel is fixed as it is a fixed quantity to install, but the labor and non-labor resources are based on how long they will work, as their cost is time related.. So it all goes well and the 20 days is achieved, it will cost as above, but if after day 5 we are slipping, there is no way for Primavera to give us an accurate forecast of cost to complete for that activity.
Please don't get me wrong, as it can be done manually, and for each resource you would have to calculate the remaining duration based on productivity to date and can capture that it, but what is the use therefore of resource loading with costs your schedule?
This is a major frustration for some years now, any work arounds to this would be greatly appreciated, as one can imagine, a construction schedule with numerous thousands of activities in gets very tedious to update if you are needing to do so many external calculations just to update the P6 schedule correctly.
I hope I have clearly expressed the issue and look forward to some responses..
Robin,
Did my reply in "The mystery of units/time period" answer your query?
I accept that after teaching hundreds of clients in P6 since 1999 my understanding of "Straight forwards" may have been affected.
I agree it is not straight forward. Adjusting remaining duration requires consideration of several factors, it is not only production rate but also what will be future resource loading. Not only started activity duration might require adjustments but also duration of similar activities not started yet.
Production rate adjustments require good tracking of to-date resource hours and to-date volume of work. But this information is not always reliable, it is frequently calculated by the software and not the real values are supplied to the scheduler.
Resource planning is useless unless there is commitment to track and manage the resource plan, nice looking bars is not good enough.
http://www.ronwinterconsulting.com/Implementing_Resource_Leveling.pdf
It is not enough to just plan your resource usage; you also have to implement your plan. This is where most projects using resource leveling fail. They define their resource leveling plan at the beginning of a project and then expect it to be valid throughout the project without adjustment. Just like a CPM Baseline Schedule, you must monitor and correct your plan as you understand the environment better and as conditions change.
Estimating activity duration using using production rates is easy, just divide volume of work [W] by production rate [W/D] of the crew to get activity duration.
[W] / [W/D] = W*D/W = D
What is not easy is the tracking of every hour worked as well as the associated cost of labor/ equipment/ material/ subcontract/ other. For this purpose some contractors [very few] use unit costing capabilities available within their financial/accounting system that will pick up every payroll hour, every purchase and therefore every penny as well as the current production units. Be aware unit-costing is not always available within job-costing as some job-costing only follow costs but not the production units. It is ironic as plugging-in the production units into the data base is quite easy.
http://www.foundationsoft.com/unit-cost-production-reporting/
http://www.aronsonllc.com/sites/default/files/2014%20S300CRE%20Variance…
Discipline is required to track actual effort and actual volumes of work. Non-rigorous methods are easy but unreliable.
Good luck.
Thanks Rafael,
This is what my frustration is focused around.
At large oracle conferences and industry leaders constant professing what the tool can do etc.
I would be interested in looking into Spider a bit.
Possibly some other scheduling tools might manage it differently or better.
Thanks
Hi David,
no its a recent post, but still no answer.
I disagree with your sentiment that this is pretty straight forward stuff however, as in all my years, this simple example cannot be demonstrated to me by anyone.
Understanding the high level roles and simplistic resources from and EPCm of Owner perspective is very simple, but if you are the executor of works and want to know where every single dollar is being spent, then this type of resource loading and costing cannot be done.
I look forward to your reply if you feel otherwise.
Regards
Robin
Using formulas we can calculate TD Prod or to date average production rate and keep track of how it varies [trends] but it does not means an automatic change. In the following example it was initially estimated a production rate of 6.25 and after first update average came out to be 2.50, it was decided to reduce it to 5.00 but not to 2.50. The initial baseline total cost was $21,200 while revised projection after first update is $25,400 for a variance of +$4,200. The initial baseline duration was 20d while revised cumulative duration after first update is 27.5d for a variance of +7.50d. The initial production rate for Activity 1 was 6.25 units/hour while after updating the average actual rate is 2.50 units/hour for a variance of -3.75 units/hour and a revised production rate of 5.00 units per hour.
No matter how you keep track of some trends it does not means an automatic change shall be applied. If you make such adjustments automatic you most probably will end up with a distorted schedule.
While Spider allows for several approaches my favorite way to track actual costs and productivity is using the financial system in place. Then we adjust schedule production rates if need be in order to get a better cost and schedule prediction. For a view of the past we use the financial system, for a view into the future we use the schedule.
Even if you do not cost your resources what is the use of updating schedule if remaining duration will anyway be wrong if you do not make timely adjustments. You have to fix it it if revised estimated duration will be different.
You can use formulas or global changes on user defined field to keep track of the average.to.date/current.period/baseline values and make the calculations within your software.
I use software that can adjust duration of production type activities based on revised production rates and resource allocations. We use it for this purpose as well as for more advanced models such as when availability of more/less productive resources/teams change and the software will look for the allocation that minimizes project duration. Anyway the resources/team production rate adjustments must be documented, analyzed and justified on a case by case.
Automatic adjustments on production rates might not be a good idea even if you figure out some procedure if using global changes for this purpose. My experience has been that estimated resource production rates are close to reality, it is the actual resource hours per period that varies. Even when using Monte Carlo the variations in production rates is considered to be very small.
It is common for a crew of 10 at times become a crew of 8 because the resources were on vacation or diverted to other more critical activity. We do not make frequent changes on resource production rates as I said before although we can, in rare occasions we feel there is need to change production rates. Our software keep track of cumulative/actual/&remaining volume of work and if the activity is of production type will automatically adjust remaining duration based on remaining volume of work and current production rates [original-usual/revised-uncommon].
Imagine an activity with an initial duration of 20 days, a volume of work of 1,000 units, a production rate of 50 units/day that on first update had 2 days elapsed duration or 10% duration but out of 1,000 units the production was 50 units for an average production rate of 50/2=25 units/day, will you calculate remaining duration as rem.units/ave.rate = 950/25=38d?
There are no shortcuts.
Good Luck
This is pretty straightforward stuff (by Prmavera standards), but I notice the post is dated 2010!!?? So I imagine you have an answer now...