All posts tagged Resources

You are here: Home / Blog / All posts tagged Resources

Jul

The Rookie Resource Mistake

Categories: Level of Effort, P6 Professional, P6 Tricks, Primavera P6 Baselines, Resources, Uncategorized, WBS Summary

Tags: Baselines, Earned Value, Primavera P6, Resources

Comments Off

by Bill Pepoon

In one of my favorite Gene Hackman films, Heist, there is a scene where his character is explaining how he solved a problem. His client (actually, a mobster he is planning to rip off) says, "you're a pretty smart guy." When Hackman's character declines the compliment, the mobster replies, "then how did you figure it out?" Hackman's response:

"I said to myself, 'what would a smart guy do?'"

I love that line. Unfortunately, I recently forgot that lesson. Let's set the stage. I am updating a new Primavera P6 schedule for the first time. I have a change order modification that has been added, and there is also progress on this new activity.

The client told me he is 40 percent complete with the modification. So I type in that percentage. And I move on with the update. But while checking my customized earnings report I realize there is no Earned Value for the new activity. But the activity is in fact showing 40% complete.

Okay...

Now, perhaps you are thinking I forgot to apply an actual start date. Well, no, it would not be possible to show a percent complete without first entering an actual start date. I should also mention that I am using the Physical % Complete type so that I can enter whatever percentage I want.

Hmm. Perhaps there is something wrong with the way I cost-loaded the activity. Nope, it has a budgeted total value. And I am using the same resource that all other cost-loaded activities have been assigned in this particular schedule.

What about my Earned Value settings? I almost never change them, but I verified that Performance Percent Complete = Activity % Complete (Admin > Admin Preferences > Earned Value). In the construction industry that is pretty much the setting that everyone uses. The point being that the activity percent complete determines Earned Value.

Yet here I am, still looking at zero dollars earned and 40% complete.

Aha, must be the activity type! We know that certain activity types like Level of Effort and WBS Summary behave differently than other types of activities.

Sorry - the new activity is Task Dependent. Nothing to see here folks. And if you were thinking it was a milestone, keep in mind that milestones cannot be assigned resources due to their zero durations.

What would Gene Hackman do?

He'd probably say something like, "hey buddy, if Earned Value is working on EVERY other activity in the schedule then there has to be something different about this one."

But it's not different, it's just new.

Oops...

Yes, it is a new activity! And where does Earned Value come from?

The baseline to the current schedule!

Under the Settings tab in the Project Details window there are two options for calculating Earned Value: Project baseline or User's primary baseline.

My schedule was set to Project baseline, and my Project baseline is the original plan. The new activity doesn't exist in the original plan so Earned Value is automatically zero.

I knew this, of course, but it is easy to forget when you are in a hurry. And it seems rather odd that users who never create baselines for the current project are immune to this potential problem. Because when there are no baselines the current schedule IS the baseline!

This is in my mind one of the most counter-intuitive aspects of Primavera P6. Earned Value is not always based on the current schedule. Why would I want to base my earnings on something other than the current schedule? If the budget has changed it seems logical to pay off the new budget.

Now, I prefer not to change the value of an existing activity for pretty much the same reason I don't change the original durations. I want to preserve the old values for future reference. If the duration or budget is changed by a modification I will add a new activity for that purpose.

I have had a few projects, however, where we re-balanced the activity budgets. Assigning any baseline other than the current schedule would clearly cause problems. Which brings up another concern: the Earned Value for a project can be okay one day and off the next if a different baseline is assigned. Fun!

When I mention this during training sessions I often hear someone with a little Primavera P6 experience say something like, "never happens to me". Yes, that could be true. If you don't typically create baselines then by default your baseline is the current schedule. Lucky you!

Those of us who utilize baselines on a regular basis have to be more careful. And it gets rather complicated when there is more than one baseline attached to the current schedule. Re-assigning a baseline can change Earned Value. Oh well. I'll just keep channeling Gene Hackman.

Sep

The Resource I Never Use

Categories: P6 EPPM, P6 Professional, P6 Tricks, Primavera Resources

Tags: Primavera P6, Resources

Comments Off

by Bill Pepoon

Resources add "weight" to a schedule. That is to say, resources can tell us the effort - in costs and/or hours - required to perform a task. Once resources have been added to an activity we now realize that tasks with similar durations are not so similar when the effort is considered.

Back in the early 1980s I would sometimes be asked by owner representatives to explain how many people were required each day in order to stay on schedule. I was using a proprietary scheduling program running on a mainframe computer in those days. It was a nice little program based on the Activity-on-Arrow (AOA) method of scheduling. But it was not capable of doing much with resources other than assign a cost value to each task.

In a parallel scheduling universe, however, Primavera Systems was offering the ability to budget and track both costs and units. The firm I worked threw in the towel in the face of a better product and switched over fully to Primavera in 1987. That was a good decision but at the time there were other scheduling programs to consider. Proximity might have helped. Our company's headquarters were across the Delaware River from Primavera Systems.

It might surprise schedulers who nearly always resource-load their schedules that a large percentage of companies - at least in the United States - rarely do so. The reasoning is often that it takes too much time or exposes confidential information. I know a lot of contractors do not want anyone knowing how many labor hours were figured into their projects.

Not knowing how many labor hours are required by the project once led to an awkward exchange with an opposing attorney during my testimony in a construction dispute:

Attorney: "Mr. Pepoon, how many people would have been required to perform this task that we are looking at right now?"

Me: "Enough people to perform the task within the planned duration."

Attorney: "But how many people would that be, exactly?"

Me: "The proper number to perform the task within the allotted time."

It sounded like a bad comedy skit, but of course I could not answer a perfectly relevant question because my client did not resource-load the schedule. And the reality is that when a subcontractor is responsible for the work the general contractor usually can't verify the duration either. He simply trusts that the subcontractor knows best.

The people performing the task would presumably know how long it takes. But no one else can verify this without knowing the required effort. Then why does this still happen? Well, general contractors pass on a lot of the risk (i.e. scope of work) to subcontractors and can always "sue the bastards" if they fail to meet the schedule. Of course, owners will then sue the general contractors for not controlling their subcontractors. Nobody will be happy.

Still, there is one resource I refuse to use - material. Anyone familiar with Primavera P6 understands that there are three types of resources: labor, nonlabor, and material. Nonlabor is mostly used for equipment, but I have another use for it as well. The trouble with a material resource is that Primavera P6 only tracks costs, not units. With labor and nonlabor resources the choices are to track units, costs, or both.

From my perspective, tracking material could be very useful. If I have moved 50 cubic yards of dirt and there is a total of 100 cubic yards, then certainly one-half of the work is complete. (I should also consider how long it took to complete one-half of the work, because productivity is important as well). This is production-based scheduling, but it is simply not possible with a material resource.

Thankfully, there is a workaround. Instead of using a material resource, why not use nonlabor instead? If it's not labor it can be pretty much anything, right? So nonlabor can be plumbing fixtures, dirt, gypsum board, conduit, or anything else we want to track. I have even used a nonlabor resource to track drawings being produced by the design team.

Both labor and nonlabor resources use "units" as the nominal description. Only material resources can have other labels, but we can easily create our own definitions.

For plumbing fixtures the unit can be "each", cubic yards for dirt, square feet for gypsum board, and linear feet for conduit. Each type of material will of course require its own unique nonlabor resource. I also indicate the real unit of measure in the description, such as "Dirt (Cubic Yards)" to emphasize the point.

I also do not show the unit label for these nonlabor resources because Primavera P6 would put "hours" on all of my nonlabor resources (Edit > User Preferences > Time Units). One other thing. When printing resource charts I do not lump nonlabor resources together because they are not the same materials at all, but this would be true for equipment as well.

Ultimately, we must decide what level of detail is required when adding resources. Minor amounts of material may not warrant much scrutiny. The desired output determines the level of input required. For example, do we need to track different sizes of piping or can they be lumped together? Too much detail is often as bad as not enough detail.

Dec

What Dollar General Tells Us About Planning

Categories: Critical Path, Planning, Total Float

Tags: CPM schedule, Critical Path, float, Planning, Resources

Comments Off

by Bill Pepoon

Those of you living in the United States are probably familiar with Dollar General stores. Mostly found in small towns, Dollar General stores sell a wide-variety of lower-priced items. But there is big money in this market. Dollar General currently has 14,000 stores pulling in $22 Billion a year. The CEO of Dollar General, John Vasos, received a lot of press recently on comments he made to the Wall Street Journal that caught my attention as well.

Most commentators seized upon Mr. Vasos’ comments that the U.S. economy was creating more of what they consider to be their core customer – someone making less than $40,000 a year. Dollar General is planning to build thousands of new stores and is moving into metropolitan areas that were not previously identified as their demographic (i.e. the arrive of a Dollar General store in some communities could be considered a backhanded compliment.)

There has certainly been a lot of debate in this country about the percentage of Americans who are unemployed or underemployed (working fewer hours than desired) and how to solve this problem. The disappearance of good paying manufacturing jobs has resulted in many individuals working somewhere else, but for a lot less money. The new job is also far less likely to offer a pension.

Dollar General and other similar “dollar” stores thrive by selling small quantities of items to lower-income households at prices they can afford. These households do not buy in bulk even though it would result in savings. Hence, they are more likely to run out of something and need a replacement quickly. I can buy a 32-pack of bottled water for about the price of three individual bottles at my favorite store so clearly buying in bulk makes a big difference.

But here is the quote by Mr. Vasos that really caught my attention. He was describing Dollar General’s typical customer:

“Doesn’t look at her pantry or her refrigerator and say, ‘You know, I’m going to be out of ketchup in the next few days. I’m going to order a few bottles.’ The core customer uses the last bit of ketchup at the table the night prior, and either on her way to work or on her way home picks up one bottle.”

In other words, the typical Dollar General customer is not a planner. They wait until they are out of something before they buy more. They overpay without thinking. This is not how we manage projects. We do not (CAN NOT) let ourselves run out of resources needed to complete a project. That would be an inexcusable delay. We figure out what we need and make sure sufficient quantities are on hand when it is needed.

The critical path of the project in particular is a difficult taskmaster. We must complete the amount of work we planned each and every work day. It is not good enough to complete tasks totaling 19 days during a 20-day work period. That puts us one day behind schedule. The critical path keeps us honest. I see a lot of arguments at the end of the month when the final tally is taken. “But we did so much work this month”, they will invariably say. “Not enough”, I will reply.

It takes a different mentality to be a planner. We have deadlines based on expectations of quality and scope of work. A bad plan leaves us uncertain as to where we should be at any given time. Every day is a deadline of sorts, because what we did not finish today becomes something else that must happen tomorrow. Granted, we have some leeway with non-critical activities but a recurring problem that I see on many projects is that the amount of float on a secondary task is exaggerated, thereby diminishing its importance. We reap what we schedule.

Planning is all about opportunity. We have many options during the planning stage. Some options are more attractive or feasible, and hopefully the least-expensive option generates the best result. But it can certainly be more complicated than that. The California Department of Transportation (Caltrans) utilizes an “A + B” approach on larger projects: each bidder must specify a contract duration and a price. Both numbers are considered when awarding projects. Caltrans’ experience is that A + B bids result in lower prices and fewer road usage delays.

The longer we wait to make decisions the fewer options that remain. Projects finish on time because we monitor our progress on a regular basis and implement mitigation strategies whenever slippage does occur. We do not use up float for bad reasons but rather to give ourselves flexibility. We do not allow ourselves to run out of ketchup.

May

The Makings of a Complicated Schedule

Categories: Activity Types, P6 Calendars, P6 EPPM, P6 Professional

Tags: Activity Type, Duration Type, P6 Calendars, Primavera P6 Professional, Resources

Comments Off

by Bill Pepoon

When does a Primavera P6 schedule become complicated? I realize that for new users it might seem like every schedule is hard; but their problem is a lack of training or experience, not the schedule itself. Schedules with thousands of activities take more time to assemble, but that alone does not make them more complicated. Besides, in nearly every schedule there is repetitive work, so we can often copy dozens (if not hundreds) of activities quickly and reuse them. If you do not already know how to do this, read Time-Saving Tricks in P6 You Must Use.

Having prepared hundreds of original plans and thousands of updates, I can say for certain that two characteristics in particular complicate a Primavera P6 schedule. There are other situations that make a scheduler’s life “interesting” but trust me, these two are the biggies:

The schedule has more than one calendar
The schedule is resource loaded

Having more than one calendar is, mind you, often a necessity. The project specifications may require that inclement weather days be added to the calendar. In other words, anticipated weather days must be blocked out similar to holidays and other non-work days. But not all activities will be affected by weather (shop drawings, permits, interior finishes, etc.) so we must also utilize a calendar that does not have weather days.

Another reason for more than one calendar would be that some activities can occur any day of the week without exception, such as concrete curing, or the project specifications identify certain tasks accordingly. So now we have a 7- day calendar in addition to a work calendar with weather, and a work calendar without weather. Just like that the schedule has three calendars!

Okay, but why is it such a big deal to have multiple calendars? To start with, strange things can happen as the schedule moves from one calendar to another. Here is one possible scenario:

The predecessor finishes on Saturday because it obeys the 7-day calendar. If the successor has a 5-day calendar, it cannot start until the following Monday. Even though both activities might be on the critical path, the predecessor will have one (1) day of Total Float while the successor has zero (0) Total Float. After all, the predecessor could have finished on Sunday and still not hold up the successor.

In Primavera P6, Total Float is relative to the activity calendar so two activities on the same path may not exhibit the same float value if they have different calendars. By the same token, activities with the same Total Float value may not be on the same path.

Here is another possible scenario: the predecessor has a calendar that is 7:00 am to 4:00 pm. The successor has an 8:00 am to 5:00 pm calendar. The relationship between them is Finish-to-Start. The successor will start the same day the predecessor finishes because there is still one hour left in the day (i.e. 4:00 to 5:00 pm). This can confuse a lot of people who never display the time of day on their schedules. They think the activities are overlapping somehow when in reality they are not.

Moving on the resources, there is a calendar issue here to consider as well. Resources cannot use project calendars. Only global and resource calendars can be assigned to resources. Our students know why we prefer to use project calendars on every project. But the moment resources are added we are stuck with global or resource calendars. There is some logic here on Oracle’s part. Resources are not project-specific and so only a shared type of calendar would be appropriate.

So think about it. We already had three calendars because of weather and the need for a 7-day calendar and now we have a fourth one! The schedule can get seriously weird at this point. What if the resource plays by different rules than any other calendar? Well, our strategy is to create a global calendar first, copy it as a project calendar, and also assign it to the resource. So the project calendar and the resource calendar are identical.

There are situations where the resource works different hours or different days and should take over in terms of calculating dates. Perhaps the resource is never available on Fridays. We have to consider whether the project or resource calendar is more important. This is why Primavera P6 offers Task Dependent and Resource Dependent activity types. There is no single right answer; it depends on the circumstances.

The question in my mind when it comes to resources is, “does the dog wag the tail or does the tail wag the dog?” If the dog is in charge then I want a Task Dependent activity. Then it won’t matter if the resource calendar does not align with the activity calendar.

Another consideration with resources is that we can allow Primavera P6 to change the activity duration – something that would never happen otherwise. Therefore, the Duration Type becomes a very big deal. Should we let this happen? It does introduce additional moving parts to a schedule that might be difficult to understand due to other reasons such as multiple calendars. Still, it does make sense that if I know the budgeted hours and the crew size, why not let Primvera P6 do the math?

And of course, if we resource-load a Primavera P6 schedule we can also resource level the schedule. I teach this in my intermediate and advanced classes, albeit with the caveat that it takes several iterations of resource leveling before we can be satisfied that the optimum answer has been found: finishing as quickly as possible using a reasonable number of resources. Not exactly something the Pharaohs worried about but for us mere mortals, time and resources are limited.

Sometimes, giving priority to the earliest activity that needs the resource yields the best result. Other times it is better to give priority to the activity with the least amount of float. If I want a very precise allocation of resources I will utilize the Activity Leveling Priority. Unless you know what all of this means then it would be unwise to resource level a schedule without guidance.

Owners may not like the idea of resource leveling because it reduces the Total Float that contractually is almost always shared between owners and contractors. But sequestering Total Float is not the idea. One of the best schedules I ever saw (that wasn’t mine) was a resource-leveled schedule on a project in Hong Kong. The owner thought it was madness but it definitely worked.

I have not touched upon everything to consider with multiple calendars and resources, but hopefully the point has been made. Complicated schedules are frequently unavoidable, often necessary, and must always be respected. Are you ready for the challenge?