Project Management Institute

The new PMI practice standard for scheduling


In early 2003, the Project Management Institute (PMI) began exploration for developing the first practice standard for project scheduling. Focus would be placed on single-project scheduling, with close coupling to the time management section of A Guide to the Project Management Body of Knowledge (PMBOK® Guide). In the summer of 2003, the project team was formed under the leadership of Douglas Clark, project manager, and Harold ‘‘Mike’’ Mosley Jr., PMP, deputy project manager. The project team would grow to include 179 members in 20 countries.

This paper summarizes how the practice standard for scheduling was developed, and outlines its significant contributions to the project management profession.

Preliminary Work

By May of 2003, the Standards Membership Advisory Group had developed an initial charter for the standard. The charter included the following characteristics for the standard:

  • Provides guidelines on developing, using, and understanding project schedules,
  • Is consistent with the PMBOK® Guide, expanding its concepts and techniques relating to scheduling,
  • Does not necessarily mirror the PMBOK® Guide processes, knowledge areas, and life cycle phases, but does provide detail and background for one or more of the inputs, tools, and techniques, or outputs,
  • Is consistent with the PMBOK® Guide glossary, providing additional entries relating specifically to scheduling,
  • Describes the processes related to scheduling that are generally recognized as good practice for most projects most of the time,
  • Is aligned with other PMI Practice Standards, and is interlinked with the material in appropriate sections of the PMBOK® Guide, Third Edition (2004),
  • Is clear, complete, concise, and relevant to defining, developing, and maintaining project schedules,
  • Includes information that is broadly accepted within the project management community,
  • Assists individuals or organizations in judging the adequacy of a project schedule, and
  • Is written for project personnel and stakeholders.

In recognition that almost all scheduling is performed using computer software, the team decided early on to build a standard that could be used by both scheduling practitioners and scheduling software developers. However, the team further articulated a rule that all processes and tools must also be able to be accomplished using paper and pencil. The subsequent development of the components list is a direct result of these concepts and rules. Additionally, the team recognized that the concept of a one-size-fits-all scheduling standard must have the flexibility to address size and complexity issues. Again, breaking scheduling into components allowed the granularity and flexibility for a wide range of project types.

In early fall of 2003, representatives from the College of Scheduling, PMI Standards Department, and the Practice Standard Team met to discuss an issue with the term schedule model. The PMBOK® Guide, Third Edition, included the term in the PMBOK® Guide glossary for the first time. The basic issue concerned the bifurcation of the term schedule to describe both the output presentation (a bar chart for instance) as well as all of the data that could produce output presentations (all of the task, dependency, and date information in a scheduling software product). The PMBOK® Guide, Third Edition team introduced the term schedule model to differentiate the output from the model. It was agreed that the practice standard team would take on a full evaluation of all terms relating to schedule. The team was to research, analyze, and then report (as part of the standard) the current practice standard for most projects most of the time.

By late summer of 2003, the core team was formed. Team members included Charles Folin, Marie Gunnerson, Tammo Wilkens, Don Green, Peter Dimov, Bethany Schoenick, Jennifer Read, Ken Cone, and Dave Hulett.

For the remainder of 2003 and most of 2004, the team focused on development of the components listing, as well as presentation and data gathering. The team presented findings to the College of Scheduling’s first, second, and third annual conferences in 2004, 2005, and 2006. Core team members also presented and garnered feedback at chapter meetings across the United States in 2004. Two opportunities to interact with the profession were used, via the Standards Open Working Sessions. The first was at the PMI Global Congress North America in Anaheim in 2004. Second, in July 2005, the team presented to over 100 practitioners at a Standards Open Working Session in Orlando, Florida.

The project team Web site, as well as the forums of the College of Scheduling Web site, provided a venue for the discussion of various aspects of the standard’s development, mostly focusing on the terms and their use. Mike Mosley provided regular liaison with the College of Scheduling Board, both to inform them of the status and project developments and to solicit support and feedback.

The team quickly found four distinct camps in the discussion of the term schedule. There were traditionalists, typically expert schedulers, who could easily move between the definitions of schedule without concern. Within this group were scheduling expert witnesses, who rightfully indicated that the introduction of a new term might affect years of case law. Next were the modelers, typically either academics or people involved in software or technology, or expert schedulers influenced by technology. The third group comprised the rank and file every day project managers. Notably, the first three camps were vastly outnumbered by the last group, the new-to-scheduling group.

The evolution of the term schedule was at the core of the Project Team’s research. Since the first issue of the PMBOK® Guide, the term had been defined without context in the profession; that is, it was just a set of dates. This did not provide reference to the method of calculation, the data needed to formulate the dates, nor the nature of the output or work product provided by professional schedulers.

The traditionalists preferred to keep the term schedule, but let it have two meanings, or lexically speaking, two senses. The modelers obviously espoused the schedule as a model, as this group looked at a schedule more as a model of what was to happen or what was happening in the project rather than a traditional plan. The everyday project managers and the new-to-scheduling groups wanted clarity. Both did not indicate a preference for resolution, yet both groups understood the tradeoffs involved.

The practice standard provided new definitions and new terms to be explicit in the various elements and phases of schedule development, implementation, and execution. Through the team’s effort, the exposure of the draft standard, and the appeals process, the terminology has been validated and provides a basis for the profession as it relates to time management.

Key Contributions

A Scheduling Process

One consistent request from the community was a clear and simple process flow for the act of scheduling. While the words required seven pages, the team was able to develop a simple graphic to summarize scheduling. Exhibit 1 illustrates the schedule development process.

The schedule development process

Exhibit 1 – The schedule development process

The Schedule as a Model

The dawning recognition that treating the schedule as a model of what is most likely to happen to a project over time, versus the plan, is one of the most important contributions to the community. In meetings with project managers, the team found a willingness and desire to have schedules communicate better, and most importantly, predict better. PMI’s own research shows that only 29% of projects can claim complete success (on time, on budget, and within scope). Further, most projects overrun time by a whopping 84%. Project managers also expressed frustration with the consistent “why aren’t we on schedule” interrogations. By changing focus to a model concept, the team is more likely to enjoy a collaborative investigation into changing the model to accurately reflect ground truth. An accurate model of today is much more likely to predict future performance than a set of dates.

Exhibit 2 illustrates a high-level view of the interrelationships between project data and the schedule model.

The schedule model

Exhibit 2 - The schedule model

Component List

Breaking up the schedule model into constituent components in the standard accomplished two goals. The first was the ability to “granularize” what could be identified as best practice or required for meeting the standard. Secondly, one standard could address both manual applications and software applications. The component list also can be used as a reference when building a schedule to understand the role of the particular component, as well as the best practice for its use. Exhibit 2 illustrates a typical component description in the components list.

Start-to-finish component

Exhibit 3 – Start-to-finish component

Conformance Scoring

The conformance scoring chapter is intended to help organizations build, deliver, and then assess the quality of their schedules. In the components listing, one attribute of a component concerns whether the component is required to be present in what the community considers a minimally viable schedule. The required components are presented in priority order, thus allowing organizations to mature from no schedules, to minimally viable schedules, to world-class schedules.

Conformance scoring table

Exhibit 4 – Conformance scoring table

Exposure and Consensus

The standard was submitted as an exposure draft in the fall of 2006. There were 347 comments. Of note, only 11 comments concerned changes to the terminology recommended by the team. The team’s comment acceptance rate (comments accepted outright, and accepted with modifications) was among the highest ever for a PMI Standard (77%). In February of 2007, the standard was presented to the Standards Consensus Body where it received unanimous approval.


The Practice Standard for Scheduling has laid the foundation for the community of project management to identify schedules that best communicate the intent of the project team. With less emphasis on the concept of the schedule as a plan and more emphasis on the schedule as a model, project teams are more likely to identify the ground truth of the project, enhancing their view of the path ahead.


Project Management Institute. (2004). A Guide to the Project Management Body of Knowledge (PMBOK®Guide) (2004 Ed.). Newtown Square, PA: Project Management Institute.

©2007 Project Management Institute
Originally published as part of Proceedings PMI Global Congress 2007 – Atlanta, GA



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