The Changing Face of CPM

The Changing Face of CPM

The advent of ever-more powerful software has relieved contractors of tedious work ranging from bookkeeping to taxes to estimating. Time that used to be spent manually crunching numbers for these and other data entry-related tasks has been reallocated to more productive endeavors. But in the course of using such software, some of the logic used to arrive at correct answers has been obscured, hidden

The advent of ever-more powerful software has relieved contractors of tedious work ranging from bookkeeping to taxes to estimating. Time that used to be spent manually crunching numbers for these and other data entry-related tasks has been reallocated to more productive endeavors. But in the course of using such software, some of the logic used to arrive at correct answers has been obscured, hidden in a maze of lightning-speed digital calculations — think tax preparation software that's helped shroud the mechanics, if not the logic, of the tax code.

While that may be an acceptable trade-off for handling some routine tasks, in others that are governed by quickly changing conditions, the need to account for multiple variables and the incessant ticking of the clock, leaving the human element out of the equation may leave contractors a little edgy. Yet when it comes to a task that meets that definition precisely — generation of a construction project's critical “on-time completion” path using the critical path method (CPM) of scheduling and managing — software is doing more of the heavy lifting.

Contractor-targeted software like Proliant from Meridian Systems, Folsom, Calif.; Primavera P3 and P6 from Primavera Systems, Bala Cynwyd, Pa.; as well as Web-based project management solutions like Microsoft Project from Microsoft, Redmond, Wash.; and from, Bedford, Mass., handles CPM along with other tasks related to planning, scheduling, and management of construction jobs. With software-enabled project management becoming the norm, electrical contractors, whether in the role of a lead contractor or subcontractor, are having to adapt to some of the challenges that software-driven CPM presents.

CPM, used to reveal and define the nature, timing, flow, and interrelationships of tasks essential to getting a project done on time, as opposed to less critical ones that have “float,” rely on all parties inputting accurate numbers and credible projections. Consequently, electrical contractors are having to be just as thorough and confident in assessing their capabilities as they were when CPM schedules were done manually or with the aid of large mainframe computers. But some question whether the emergence of software has taken the rigor out of CPM and reduced its effectiveness.

More attention to detail

In many respects, software-enhanced CPM has improved the application of CPM, says Dan Pigott, vice president in the corporate project management office of Henkels & McCoy, Blue Bell, Pa. But even as it's made CPM a more robust and valuable project management tool, software-driven CPM has required the company to be more mindful of how it develops a CPM schedule. Having that tool is important, Pigott says, but even more important is knowing how to use it properly. Detailed task descriptions, resource availability grids, and task duration projections must be carefully assembled prior to inclusion in a CPM schedule, which powerful software generates based on data input prior to a project's start, he says.

“On any size project, if the level of detail of the schedule is insufficient to define the actual sequence of the work, or the network logic utilized to define the interrelationship of activities is incomplete or incorrect, the economic benefit of CPM will be lessened and the schedule reports will not correlate with what is being done in the field,” Pigott says.

To ensure Henkels & McCoy's CPM calculations and contributions are as accurate as possible, Pigott says all key members of a project team must be involved.

“Getting the full benefit of CPM, particularly resource-loaded and -leveled CPM schedules, requires experience with the software tool and experience in properly creating the network logic for the schedule based on field construction personnels' approach to the project,” he says. “Having the proper support for the project teams in development of the schedule logic is important in achieving the advantages of CPM.”

Moreover, Pigott says, all CPM contributors, not just designated project managers, should understand how it works once it's in place. If they don't, they may not fully buy into it, which means CPM can end up languishing.

“CPM's main disadvantage is that it is generally viewed as complex by field personnel,” he says. “A lengthy schedule report can be intimidating — never mind the network logic diagram. This can be addressed over time through training and by providing the support.”

But in general, CPM's incorporation into both client server/desktop-based software and enterprise software used in Web-based, network-server applications has probably boosted its value as an ongoing project management tool. In Web-based applications, in particular, the ability of all parties to collaborate and quickly update schedules that may impact the critical path is greatly enhanced.

Updating important

That's been an important leap ahead for CPM's value in project management, says Dave Firestone, president of Commonwealth Electric Co. of the Midwest, a Lincoln, Neb.-based electrical contracting firm. While Commonwealth doesn't encounter CPM on every job, and often uses a more basic form of it available in scheduling software from Primavera Systems, it recognizes that CPM's value today rests not only on solid information going in, but also on regular updating going forward.

“A schedule is only as good as the information put into it, says Firestone. “It's one thing to develop a schedule and another to use it to manage a project. Most companies using it today have people who understand how CPM works and are capable of developing it. But it's important that when there are changes that affect the critical path, they're put into the schedule. When an activity is missed, it's actually looked at and transposed into the schedule to see its effect on the critical path. CPM has to be managed; it's not something that people can put up on a wall and say it will run by itself.”

With more software-based CPM in the hands of owners, construction managers, and general contractors focused ever more intently on bringing projects in on time and on budget, the likelihood of CPM being mismanaged is decreasing, says Wayne Griffin, president of Wayne J. Griffin Electric, Holliston, Mass.

“Software is allowing more people on a job to deliver the information that's needed to keep CPM schedules updated,” he says. “That ease of availability, along with the fact that more people are managing project schedules, means CPM is a powerful tool to supplement a contractor's responsibility to execute a skilled project. But updating and statusing at least once a week is important, because if the critical path is missed it produces a ripple effect. There's often not too much time to recover.”

Not all CPM software, however, provides the same degree of control over a CPM schedule. Versions that allow for schedules to be resource-loaded and leveled (adjusted based on the availability of manpower and machinery, for instance, that may be need to be deployed concurrently or sequentially on critical path activities) can be especially helpful in keeping a CPM schedule updated and relevant.

According to Pigott, some CPM enterprise software does not currently offer users the ability to adequately employ resource leveling. Software that does, however, allows contractors to develop plans and schedules that are more cost-effective and efficient.

“During construction, the updated (resource-loaded and -leveled) CPM schedule provides management with forecast information, facilitates re-planning as the project progresses and/or scope is modified, and assists in documenting an event impact such as third-party delays,” he says. “Knowing the forecast impact then enables a project team to evaluate alternatives that potentially mitigate the effect of such an impact.”

Creating a dynamic path

Another advantage that some software applications have brought to CPM analysis is the ability to massage the critical path by assessing the impact of possible changes. Such a “what-if,” “what-might-happen” capability gives project managers a chance to use the power of software to pose hypothetical situations and see what impact those would have on the critical path.

“If you know the critical path and have identified the major activities that feed into that, you can identify areas that may cause problems down the road,” Firestone says. “When you identify them, you can plan to go into overtime mode, extend the project, or figure out other ways to deal with them.”

CPM schedules that are routinely monitored and updated offer the best chance to pose “what-if” scenarios, Firestone adds. “If CPM is used correctly, it's a good tool that can allow you to look out four weeks or so,” he says. “CPM allows you to work backward from the end of the project and say ‘these are the things that need to happen’ to get to an end date that you can't go beyond.”

Without question, user-friendly software has handed contractors and others involved in construction projects greater control over CPM, helping to demystify a tool formerly wielded by select practitioners of advanced project management. But that shift has troubled some traditionalists who breathe some of the rarified air within the project management and scheduling community. Some experts in the derivation and application of CPM have suggested that greater ability to fiddle with CPM schedules inside powerful software exposed CPM to potential abuse and misuse by those who use it — even eroding its value as a mostly ironclad project management tool.

Making CPM work better

But vendors of scheduling programs that incorporate CPM insist that software have only made CPM more powerful by integrating it with other scheduling tools. Plus, it's given more of those involved in project management hands-on access to a scheduling and management element that's still essential in most any job.

A representative of one such vendor told EC&M that software, in general, has had the effect of making CPM more flexible and versatile. While “there is a way to go about CPM that is very orthodox,” the representative says, CPM is enhanced when project managers are able to use it with other scheduling and management tools that can be adapted to the different ways in which construction projects are structured.

“CPM remains a core methodology and our software adheres to that by calculating ‘float’ and the forward and backward path of a project,” the spokesperson says. “It's interesting to see the different ways that people are using CPM today, but the bottom line is that it's still CPM.”

For electrical contractors like Griffin, who have witnessed the evolution of project management over the course of some three decades, CPM has only grown to be a more powerful tool. Software has certainly helped, in the sense that it's enabled those involved in projects at multiple levels to stay focused on one of the few things more important than getting a job done and done safely: getting it done in a timely, cost-effective fashion.

“A project's plan for completion is one that has to be followed, but also modified, adjusted, improved, or even extended,” Griffin says. “CPM is a guide and a map to assist in the planning process, but one that has to be molded and developed as it evolves.”

Zind is a freelance writer based in Lee's Summit, Mo.

Sidebar: Plugging the Holes in CPM

While the critical path method (CPM) is adapted to more construction management software suites, the search continues for even better ways to handle the monumental challenge of scheduling. That quest has led some electrical contractor project managers to look beyond CPM and other entrenched scheduling and project management processes to new ones that may work better and make more sense from a practical standpoint.

One such manager is Christine Rahlf, project manager for Town & Country Electric, a commercial-oriented electrical contractor based in Appleton, Wis. Well-acquainted with CPM and how modern-day software has supercharged its application, Rahlf sees fundamental faults in how it's actually applied. Too often, she says, CPM doesn't account for many of the “on-the-ground” realities that really impact whether a project is able to stay on track. Specifically, traditional schedules developed via CPM often fail to reflect and account for the daily interface that takes place between multiple subcontractors whose routine tasks are often intimately linked.

“The reality is that my guy is going to spend less time looking at a schedule that's been drawn up than he will talking to the concrete guy about how to get a floor box in,” she says.

So Rahlf is increasingly attracted to an emerging concept called Last Planner, a system developed by Lean Construction Institute, a non-profit research organization based in Louisville, Colo., that seeks to account for more of minutiae work that takes place daily and even hourly on job sites — and have those interactions play a bigger role in pulling work to on-time completion rather than having a schedule pushed from above.

“Last Planner attempts to bridge the gap between what's on paper and what's actually happening between the different trades on a job site,” Rahlf says. “A lot of the daily interfaces that take place don't show up on a CPM schedule. With this system, based on lean construction principles, interrelations between the trades are identified and better managed — and scheduling and planning is done on a daily basis.”

Using this system, each trade has to commit to what will be done and identify what would prevent that from happening, Rahlf explains. “Then, the following week, say, you look at what got done and what didn't and why or why not, and you analyze the deviations,” she says. “It throws CPM on its tail because instead of scheduling tasks as early as possible to preserve the float, you're scheduling tasks as late as possible and creating a situation where the contractor can approach a job from a pull standpoint rather than a push.”

Used by a growing number of contractors, Last Planner can be implemented in a software application that has been created by Lean Construction Institute, Rahlf says. It can be deployed along with traditional project management software as well.

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