Technical Program Abstracts

(PS) Planning and Scheduling

(PS-2390) Critical Path Shift: Everything You Need to Know

Authors: Mark F. Nagata, PSP; William Haydt

Abstract: Due to the dynamic nature of construction projects, the critical path can and often does shift from one work path to another work path in response to progress and project events.  Identifying precisely when a critical path shift occurs is essential to assigning delay to both the responsible critical activity as well as the responsible party, and ultimately to determine whether delays are excusable and compensable.  Correctly identifying when a critical path shift occurs can determine whether an owner assesses liquidated damages or grants a time extension and, if applicable, pays a contractor for its delay damages.  Critical path shifts vary from the obvious to the hidden, even the arcane.  For example, it is possible for non-critical work to be delayed only a day and result in a critical path shift and project delay of a day or more, which is a characteristic of a critical activity.  This seems counter to common wisdom.  This paper will explain how this happens, define what a critical path shift is, identify its two basic causes, and provide examples to demonstrate precisely why and when a critical path shift occurs.


(PS-2407) Alternate Methodology for Managing Large Complex Project Schedules

Authors: Abbas Saifi; Greg M. Hall, PSP

Abstract: Projects are becoming increasingly complex and the industry is demanding schedules that can keep pace with that trend. This has made a project scheduler’s job more complicated than ever.
The project team and project scheduler must capture key activities in the project schedule, and must properly justify why they are important. The project team, in their effort to capture such key activities, may resort to micro managing a project, rendering the project schedule extremely tedious and time-consuming to maintain and update. Alternatively, the project team, in an attempt to minimize the number of activities and thus day-to-day-workload, may omit crucial activities.
This paper discusses the disadvantages of micro managing a project; highlights the vital deliverables that must be looked at; and introduces the concept of master project and sub project as a means of managing such complex schedules. The implementation of this method, with significant care, will allow the scheduler to both generate key reports with ease and satisfy the objective to assist the project team in performing risk assessments.


(PS-2412) Protect Your Project Schedule Using the Unified Scheduling Method

Authors: William W. Davis

Abstract: Many projects suffer schedule overruns.  Building a schedule that leads to on-time delivery requires balancing the need for schedule safety with the need to complete the project as quickly as possible.  Using the Unified Scheduling Method (USM), project planners can create a right-sized schedule reserve by forecasting how many critical path activities will suffer schedule delays, then building a schedule reserve to buffer the schedule so the project still finishes on-time.  USM relies on the binomial distribution functions inside Microsoft Excel® to determine how many activities are at risk of schedule failure.  Once that is determined, project planners can choose from among a conservative, moderate, or aggressive schedule reserve.  This approach gives project sponsors and planners a way to balance their need for schedule safety with the competing need to finish projects quickly.


(PS-2413) Extracting the Resource-Constrained Critical/Longest Path from a Leveled Schedule

Authors: Thomas M. Boyle, PE PSP

Abstract: Heuristic (i.e. rule-based) resource leveling is the only method explicitly provided for avoiding resource conflicts in the dominant North American scheduling tools, but it seems largely rejected in the construction industry because conventional Critical Path definitions and corresponding Float calculations in leveled schedules are wrong or misleading.

The author describes an automated method for accurately depicting the Resource-Constrained Driving Path to project completion – i.e. the Critical Path – in a leveled schedule.  The method infers resource-driven, Finish-to-Start links between time-adjacent activities based on detailed examination of the corresponding resource assignments and leveling data.  These latent links can then be incorporated into a robust routine for tracing and reporting driving logic.  The method is demonstrated in Microsoft Project; implications for a similar approach in Primavera P6 are outlined.  Limitations of the method are explored and described using standard resource-loaded schedule models.

The sequence of activities in a leveled schedule are notably unstable.  This method allows practical and repeated use of automatic resource leveling while maintaining a clear definition of the true Critical Path through the project.


(PS-2425) Jobsite Photography Should Be a Scheduler’s Job

Authors: Ronald M. Winter, PSP FAACE

Abstract: Schedulers should be doing more than just noting jobsite status; they should be documenting it.  Jobsite photography should be a part of the daily, weekly, or monthly status inventory that schedulers perform.  Arrive too early and the photographer might miss documenting part of the work.  Photograph the work too late and it may be obstructed by new work.  Site conditions at the moment of project delay must be timely noted.  Timing is everything and that is a specialty where schedulers should excel!

This paper discusses the unique talents that the scheduler can apply to documenting work status.  If a job is to be done, then it should be done correctly.  It is not enough to just snap a picture; the subject should be relevant to the pertinent project issues and should be clearly visible, well annotated, and easy to retrieve when needed.  Clear, easy to reference documentation does not just happen; it requires knowledge and planning which are both traits of a good scheduler.


(PS-2427) P6 File Corruption, Part 2

Authors: Ronald M. Winter, PSP FAACE; Marina G. Sominsky, PSP

Abstract: An earlier paper by the authors introduces the topic of P6 File Corruption and endeavors to separate reality from perception. This paper further explains exactly how to repair cases of known corruption using the tools provided by the database server, as well as by Oracle® Primavera P6?. The deficiencies of the original Primavera P6? Check Project Integrity routines are explained in an effort to make this utility more useful to IT experts or even P6 users, should this functionality be restored in the Oracle® Primavera P6 Professional? or the Oracle® Primavera EPPM?

The main emphasis of this paper is a dedicated research of the prevalence of P6 file corruption in the scheduling community and the types of problems experienced. To this end, the authors have developed a software research tool and invited various P6 users to participate in the discovery of this issue. Two PSP certified schedulers, who are also IT experts, present this unique paper on the subject of P6 File Corruption.


(PS-2428) Improving the Update Process: Solutions for a Contentious Industry

Authors: Greg M. Hall, PSP

Abstract: Change is inseparable from construction, yet the owner/contractor cooperation necessary to properly deal with it varies widely from project to project.  Specifications require detailed, regular schedule updates and numerous reports, but much of what the contractor generates to meet those specifications is either rejected by the owner, of questionable value, or ignored.

To make matters worse, each party often responds to change in a manner that best protects its interests: contractors protect profit margin by refusing new risk, or seeking high compensation for it; and owners control program cost while keeping delivery commitments to the public or shareholders.  While cost certainty benefits both parties, potential change orders often languish up to—or beyond—project completion.

This paper addresses unresolved delays by examining past projects’ practices of schedule updating, Time Impact Analysis, handling Resource-Driven Logic, and the parties’ communication of the data generated by these processes.  By emphasizing “LP23” reviews, Progress-Only update states, and acting in the project’s best interest, this paper addresses how both parties can meet their divergent goals and avoid disputes.


(PS-2432) How to Plan with Line of Balance

Authors: Aldo D. Mattos, CCP

Abstract: Roads, pipelines, multi-family housing complexes and high-rise buildings are examples of projects with an intrinsic characteristic of repeatability, i.e., in which a group of activities are performed successive times. Network scheduling methods such as PERT-CPM have proven successful in the planning and control of projects, but are not as suitable for projects of a repetitive nature. Line of balance (LOB) is a planning technique developed for this type of project. A repetitive operation can be represented by a straight line on a time-location graph. Its slope is the production rate at which the activity advances. In this paper, the author intends to show how to calculate and plot lines of balance and demonstrate the relevance of planning with LOB and its advantages for project controls. Two case studies are addressed.


(PS-2491) Implementation of the Half-Step Analysis During the Project Phase II

Authors: Brian J. Furniss, PE CFCC PSP; Cory Milburn, CFCC PSP; John P. Orr, PSP

Abstract: The Half-Step, or bifurcation, method of schedule updating and analysis is used to segregate the effect on the schedule caused by activity progress and schedule revisions (changed durations, added activities, activity relationships, or other non-progress factors).  The comingling of progress updates and schedule revisions often results in an inconclusive assessment of schedule status when compared to prior schedule updates.  Additionally, schedule revisions may conceal other issues with progress or production delays.  While this process is often used after the project to identify delays, we propose expanding its use during the project as a way to objectively assess performance, discuss the plan moving forward, and resolve potential disputes.

Phase I of this topic was drafted by John Ciccarelli, Michael Bennick, and Brian Furniss, and was presented at AACE’s 2016 Conference in Toronto (CDR-2305). This paper builds upon the principles from Phase I and provides technical examples of the half-step application, including real-life case studies and interpretation of what the data may, or may not, tell the user.


(PS-2528) Understanding the Elements of a Good Project Schedule

Authors: Chris Ackerman; Kyle Chudzinski

Abstract: Having a “good” schedule is a key component to ensuring project success. The phrase, “that’s a good schedule” may vary in meaning among project practitioners depending on their backgrounds and roles. The purpose of this technical paper is to share some proven ways to consistently perform a schedule quality review. Utilizing information from organizations like AACE® International and Independent Project Analysis, as well as other industry-recognized best practices, the project control office at Marathon Petroleum Corporation has developed an internal process of reviewing and benchmarking factors that indicate what constitutes a good schedule. These methods have brought consistency to the schedule review process which has allowed the project teams to gain more confidence in the information that the schedule portrays. This confidence allows the project teams to rely on the schedule as a tool to make critical decisions increasing the likelihood of project success.


(PS-2529) Critical Nightmare

Authors: Hans Du Toit, PSP; Sean Vermaak, PSP

Abstract: There is a multitude of statistical information that points to the failure rate of Mega projects in today’s project environment. Many reasons are put forth as underlying factors that are the main culprits for this scary statistic, such as; complexity of the project, inexperienced personnel, unrealistic expectations, only to mention a few. As such the importance of proper preparation for mega projects cannot be overemphasized. Although there are a multitude of best practices to consult in preparation for and execution of Mega projects, there appears to be a lack of experience feedback, through examples to which people can relate, that demonstrate possible pitfalls.

Having had to deal with various issues experienced on a Mega project in the power generation industry, the authors, through this paper seek to provide tangible examples and possible remedies of some of the pitfalls to be considered during project planning and execution.


(PS-2593) (Panel Discussion) The Great Debate - CPM Scheduling - Owners vs. Contractors

Authors: Jeffrey Milo; John Orr

Abstract: CPM scheduling has become a standard requirement in construction contracts between Owners and Contractors.  These parties are all too frequently at odds in the effort to prepare a single schedule that meets both their needs.  Sometimes the rules (in the form of contract specifications and recommended practices) can make this process more confusing instead of less.  Interpretation of the specification requirements, misunderstanding of the baseline schedule review/approval process, sequestration of float, unbalanced cost and resource loading, incorporating impacts and changes during the updating process  all of these can be the subject of contention and debate between owners and contractors.  This session will present a panel of Owner representatives and Contractor scheduling managers to discuss and compare their interests, goals, actions and options during the schedule preparation, review, and updating process.  Although presented in a debate format, the goal of this session is not to determine a winner, but to reach agreement on shared goals and viable solutions that benefit both parties and to make the CPM schedule a tool, not a contest between Owner and Contractor.


(PS-2649) Portfolio Management in P6

Authors: Molly I. Donaldson, CCP

Abstract: Oracle® Primavera P6SM has built-in functionality that allows the user to group projects into portfolios and to then perform analysis on those projects as a group. Portfolio analysis is used to group sub-projects into the overall project and to group individual projects into a group for management within the organization. This paper details the process of creating and using portfolios, displaying portfolio data, and examines the behind the scenes calculations performed by the software to provide portfolio level data such as performance status and Earned Value metrics. In addition, the differences between Primavera P6SM Professional and Primavera P6 SM EPPM are considered for portfolio management.


(PS-2658) Categorizing Schedule Activity Relationships for Logic Analysis

Authors: Paul Reeser

Abstract: This practical applications paper demonstrates how to categorize relationships into Six major groups (Fragnet, Crew, Phase, Milestone, Change Order, Anomalies) so that logic analysis can be executed quickly and simply.  Software products to be used include standard scheduling software such as Primavera P6® or Microsoft Project®, as well as spreadsheet software such as Microsoft Excel® or OpenOffice Calc®.  Once grouped into their respective categories, two main benefits are found; viewing relationships for consistency and discovering issues more easily than in the native scheduling software.  This paper uses actual projects as references, and will demonstrate to the user how to setup data tables and formula columns to categorize the relationships and identify typical issues.


(PS-2670) Draft Recommended Practice No. PS-23 – Analyzing Near-Critical Paths

Authors: Dr. Amin Terouhid, DRMP PSP; Dr. Maryam Mirhadi, PSP; Thomas M. Boyle, PE PSP

Abstract: This Recommended Practice (RP) is intended to provide a guideline on analyzing near-critical paths in project schedules. Delays or unexpected circumstances may adversely affect near-critical path activities to the extent that they become critical. A near-critical path consists of one or more near-critical activities that are susceptible to the risk of becoming critical and/or causing critical path delays.

This RP will discuss the term near-critical path and the significance of near-critical paths in projects; demonstrate how to determine near-critical paths; and set forth a process for tracking, trending and analyzing near-critical paths. This RP is intended to serve as a guideline and resource, not to establish a standard.


(PS-2681) The Behavior of Resource Critical Schedules

Authors: Brandon Atkins, PE

Abstract: Resource-critical schedules are defined by the inclusion of resource-driven, preferential logic in the critical path.  Such a schedule with many preferential logic ties will also have many mitigating re-sequence alternatives within the critical path.  If delaying an activity on the critical path has no impact on the completion of the project, is that activity truly critical? The resources driving those critical relationships determine the longest path rather than the activities themselves.   Do the concepts of critical path and float apply to such a schedule?

No project has infinite resources and therefore most real schedules will include at least some resource-driven logic. This paper seeks to describe what is meant by resource-critical and characterize the behavior of resource-critical schedules particularly when subjected to delays or disruption. Understanding resource-critical schedules is of particular importance to specialty contractors where resources tend to be more limited and the logic tends to be preferential and driven by resource availability.

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