PM constraint theory--a new category of constraints to ensure positive outcomes



In difficult economic times, “doing more with fewer resources” requires smarter planning and new concepts to help your projects succeed. This paper introduces the new concepts of project management constraint theory and a category of constraints to ensure positive outcomes. Definitions of constraints and risks are analyzed.

Project management constraint theory is the identification, definition, categorization, utilization, modification, planning, implementation, and control of project constraints. Constraints may be grouped into categories. A new category of constraints, presented in this paper, is called constraints to ensure positive outcomes (C-TEPO), a set of rules affecting a project to bring about positive outcomes and to enhance project performance and success.

  • An example of C-TEPO is the requirement by an organization that earned value measurements and reports be required in a new project. This constraint is mandated so that ongoing schedule and cost variance information will be reviewed regularly by management for the purpose of applying corrective action quickly, if needed, to make the project successful.

Another category of constraints was described by the author in a previous paper (Kozy, 2008). This paper presents a sample project that demonstrates how to apply these new concepts, with tools and methodology to identify and develop project constraints. A template and processes are included for project managers who want to apply these concepts to their future projects to help ensure their success, to produce tangible and/or intangible benefits, and to show the value of their project management.

Definitions in the PMBOK® Guide and Examples

Constraint. The state, quality, or sense of being restricted to a given course of action or inaction. An applicable restriction or limitation, either internal or external to the project, that will affect the performance of the project or a process.

  • For example, a schedule constraint is any limitation or restraint placed on the project schedule that affects when a schedule activity can be scheduled and is usually in the form of fixed imposed dates” (Project Management Institute [PMI], 2008, p. 421).

Risk. An uncertain event or condition that, if it occurs, has a positive or negative effect on a project's objectives” (PMI, 2008, p. 438)

  • Example of a negative risk (threat): An equipment supplier notifies you that it may not be able to deliver your order on the date expected in your project schedule. As the equipment's delivery is on your critical path, this uncertain event, late delivery, could result in a later-than-expected project completion.
  • Example of a positive risk (opportunity): An equipment supplier notifies you that it may be able to deliver the project's order two weeks earlier than expected in your project schedule. As the equipment's delivery is on your critical path and the installers are able to install the equipment early, this uncertain event, early delivery, could result in an earlier-than-expected project completion.

Assumptions. Assumptions are factors that, for planning purposes, are considered to be true, real, or certain without proof or demonstrations.
Assumption Analysis. A technique that explores the accuracy of assumptions and identifies risks to the project from inaccuracy, inconsistency, or incompleteness of assumptions.” (PMI, 2008, p.419)

  • Example of an assumption: Your organization will not close, run out of funds, or cancel your project.

Key Differences Among Constraints, Risks, and Assumptions

Constraints are different from risks because the causes of each constraint are certain and have either a 100% probability of occurring or no probability of occurring (See Exhibit 1: Graphical and Mathematical Representation).

  • Examples of common constraints described in A Guide to the Project Management Body of Knowledge (PMBOK® Guide)—Fourth Edition (PMI, 2008) include limitations, usually predetermined by the organization management before project execution—e.g., “predefined budget or any imposed dates or schedule milestones that are used by the customer or performing organization. When a project is performed under contract, contractual provisions will generally be constraints” (PMI, 2008, p. 115)

Risks, on the other hand, are events having a “probability” of occurring that is less than 100% percent and greater than 0% (see Exhibit 1). Risks can be categorized, prioritized, and identified before or after project execution begins. (PMI, 2008, pp. 279–281)

Graphical and mathematical representation of the differences. between risks and constraints

Exhibit 1: Graphical and mathematical representation of the differences. between risks and constraints.

Assumptions generally involve a degree of risk and therefore, have some probability of occurring (>0% and <100%) (PMI, 2008, p. 287). Assumptions are usually determined before project execution.

This paper describes categories of project constraints as positive, useful concepts and views these concepts as helpful to project success; they are not obstacles to be eliminated, unnecessary restrictions, or limitations on freedom of action. This view contrasts with the view of Theory of Constraints (TOC) (check) by Eliyahu M. Goldratt (1999) which presents constraints as negative items or events that hinder workflows and production output and, thus, considers them as obstacles to be eliminated, one by one.

New Definitions: Project Management Constraint Theory and Categories of Constraints

Project Management Constraint (PMC) theory is the identification, definition, categorization, utilization, modification, planning, implementation, and control of project constraints. These project constraints are sets of rules that ensure positive outcomes or avoid negative outcomes that respectively increase or diminish project performance and success.

  • Definition of project performance, success, rules, and constraints may be determined outside of the project or may be determined by the project manager, team, stakeholders, or sponsors.
  • Constraints may be grouped into categories, such as: constraints to ensure positive outcomes (C-TEPO) and constraints to avoid negative outcomes (C-TANO).

Constraints to ensure positive outcomes (C-TEPO) is a special category of constraints where before project execution and prior to approval of project changes, the project team identifies, defines, communicates, and implements constraints in order to ensure positive project outcomes and add tangible and/or intangible benefits to the project.

  • These constraints have the state, quality, sense or instruction of being restricted to a given course of action, or inaction, in order to enhance or exploit opportunities and ensure positive outcomes to the project. These constraints may be determined by external, organizational, or project sources.
  • This category of constraints focuses on enhancing or exploiting these types of positive outcomes: project completion on-time or earlier than scheduled; project completion at a cost equal to or less than budget; revenue generation for the project or sponsor; improved return on investment; standardization of project methodology and expectations; meeting requirements to the satisfaction of the customer or stakeholder; quality expectations for the resulting product or service; team ethical behavior; team safety; team confidence and focus; job satisfaction and personal growth goals; improved teamwork; respect for team members, clients, and customers; improved customer relations; and project success.
  • Example 1. The organization decides to order equipment for the project only from suppliers who have an excellent track record of on-time or early delivery of orders and who agree to payment of significant penalties if equipment is not delivered on-time.
  • Example 2. The organization's project management office (PMO) decides to incorporate Aspirational and Mandatory Standards for Responsibility, Respect, Fairness, and Honesty from Chapter 2 of the PMI Code of Ethics and Professional Conduct® (2006) into this Project's C-TEPO. The decision may originate from the belief that use of such a code of ethics by an organization's project managers definitely will ensure the success rate of a project by setting high ethical and positive expectations for behavior of the project manager.

In 2007 and 2008, the author presented the project management concept of Constraints to Avoid Negative Outcomes (C-TANO) at the PMI global congresses held in Atlanta and Sydney, respectively. (Kozy, 2008)

  • Example of C-TANO: the sign found at commercial construction Project sites requiring that “hard hats” be worn by everyone at that site to prevent tragic injuries (see Exhibit 2).
Construction Site Signs in Australia are examples of C-TANO to avoid injuries

Exhibit 2: Construction Site Signs in Australia are examples of C-TANO to avoid injuries.

“To Go” restaurant parking sign in the United States is an example of C-TEPO used to solve the parking problem while maintaining positive customer relations through the humor

Exhibit 3: “To Go” restaurant parking sign in the United States is an example of C-TEPO used to solve the parking problem while maintaining positive customer relations through the humor.

Tools and Methodology

Tools to Help Identify Project Constraints

Tools to help identify project constraints include: brainstorming (PMI, 2008, pp. 286, 428), root cause analysis (PMI, 2008, pp. 204, 447), “5 Whys” (Liker, 2004), and fishbone diagrams (PMI, 2008, pp. 208–209, 287). This paper presents a new tool: the project management constraint template (Exhibit 4). The project team and stakeholders need to work together to understand the project and its full scope in order to effectively use these tools to develop such constraints. A by-product of this process is that the project team may improve their level of understanding and buy-in, thus increasing the chances of success for the project.


Using the column headings in the template (Exhibit 4), the identification process of project constraint management begins with entries into the first column, Project Objectives. Here all of the objectives of this project are listed; these are gathered from the project charter, scope and project management plan documentation, including the project requirements. This complete list of objectives is necessary before brainstorming for identification and categorization of outcomes and their resultant constraints in the columns to the right. Next, define what are the considerations and consequences, or what reasons are behind or leading up to each of these objectives (the answers to “Why?” for each entry in Column 1); then, enter the answers into Column 2. Based on the information in the first two columns, brainstorm and enter a list of positive outcomes desired (Column 3) or of negative outcomes to avoid (Column 5). Finally, a list of corresponding constraints is developed by the team and entered into their respective categories in Column 4 or 6.

Project Management Constraint (PMC) template. (Six columns; add rows as needed.) See “process,” “using the tools,” and “cautions” for guidelines for each cell entry in the table

Exhibit 4: Project Management Constraint (PMC) template. (Six columns; add rows as needed.) See “process,” “using the tools,” and “cautions” for guidelines for each cell entry in the table.

Using the Tools

For each entry in the columns (progressing left to right), use brainstorming techniques and root cause analysis to determine the underlying reasons and to derive the resulting constraints. Use the “5 Whys” tool when stuck on an item; for each entry, ask “Why?” five times (once for each answer given). The root cause(s) should become clearer with each answer. The results of these tools to identify constraints in the sample “To Go” project are shown in Exhibit 6. (Due to limited space, related entries in Exhibit 6 are grouped by color (highlighted) and tagged as (A), (B), (C), (D), (E), and (F) in order to show their logical relationships and connections across the columns.)


Some team members may be tempted to start by listing all of the obvious positive or negative outcomes in the PMC template. However, to jump ahead or start elsewhere must not be allowed. Instead, starting with a complete list of project objectives ensures that each positive outcome or its opposite will be considered. This control is necessary in order to complete the brainstorming process in a logical manner, starting from the column on the left and working to the columns on the right. After careful review, some outcomes or constraints developed by the team may be determined to have less than 100% probability of occurrence; by definition these are risks, not constraints. Upon approval of the team, you should move those selected risks to your formal risk management analysis. Remember: do not include standard operating procedures as constraints or risks.

Diagram Tools

Cause/effect, Ishikawa, and fishbone diagrams are considered the same tools (PMI, 2008, pp. 208–209, 287). Applying such a diagramming tool makes it easier to graphically display, visualize, understand, and define constraints by specifying the key goals and outcomes desired, and then determining their causes. Enter an overall goal in the box on the far right (see Exhibit 5). To the left of the goal box, identify and enter the desired outcomes that will result in the goal. To the left of the outcomes, enter the key contributors and the constraints that would ensure the positive outcomes (top half of diagram) or would avoid negative outcomes (bottom half of diagram) in order to accomplish the outcomes and overall goal. Grouping the constraints within topic areas such as people, technology, environment, method, time, energy, measurement, and materials can help the team brainstorm.


Identify constraints before project execution and prior to approving project changes: The project management constraints need to be identified before the list of project tasks can be finalized. However, once the project tasks begin to be executed, the team again looks for project management constraints:

  • In progressive elaboration (PMI, 2008, p. 7, p. 442), as more details of the project management plan that is being executed are discovered, a review of these details and how they affect the project results provides an opportunity to analyze whether any additional constraints or risks need to be identified. This activity occurs before any changes to the project plan are approved and put into execution via the change control system (PMI, 2008, pp. 98–99, 338, 428).
  • Activation of responses to project risk events that actually occur during the project execution may initiate tasks that result in the need to identify additional constraints and risks, or changes to existing ones.

Sample Application of Categories of Constraints to a Modern Project

Background of a “To Go” Project

A major trend exists where some global restaurant chains are expanding their businesses by offering “To Go” service to their customers. That is, in addition to dine-in service, the restaurant offers a “carry-out” or “take-out” option to customers who do not have time to dine inside the restaurant, whereby these customers can call ahead and order from the same menu, then drive to the same restaurant to pick up the custom-prepared food curb-side to take back with them to their home, office, or next destination. Restaurants offering “To Go” service usually have been designed to be free-standing buildings, with plenty of parking close to the restaurant building for all of their customers. Therefore, this sample “To Go” project contains both layout design and restaurant service expansion requirements for renovations.

This “To Go” offering is not to be confused with fast-food drive-through purchases (e.g.. McDonald's), or ordering pick-ups inside a restaurant (e.g., pizza or Chinese carry-outs). Upscale “To Go” restaurants have their same full lunch and dinner menus at their normal prices (e.g., “Chili's” and “Outback Steakhouse” chain restaurants). These restaurants offer individual, custom-prepared food from their dining menus for “To Go” customers.

When the “To Go” customers arrive at the restaurant, they expect to park curb-side near the restaurant where an employee (called a server) sees their parked vehicle and brings out their appropriately packaged preordered food and bill to the vehicle. The customer may pay by cash or by credit card; and then drive away. This exchange should take less than five minutes at the restaurant site.


To Go” business can mean significant added revenue for these restaurants while their dine-in facilities are not disrupted. They use the same kitchen staff and simply add a phone order-taker/cashier and a “To Go” server to be sure the food is correctly packaged and quickly delivered to the customer's vehicle.

C-TEPO Ensuring Safety

The physical safety of the “To Go” servers, cashier, and customers in the parking area is a required goal. If anyone is hit by a vehicle, then, in addition to the pain and suffering of the accident victim, the business operation will be seriously disrupted. Using brainstorming and a fishbone diagram (see top half of Exhibit 5), entries for C-TEPO are developed and mapped to entries (A) and (B) of Column 4 in Exhibit 6. These constraints require: servers to wear bright yellow reflective vests; the design/construction of a dedicated, close-by door near the curb-side parking; and a marked, signed, and well-lighted parking area by the curb for exclusive use by the servers and “To Go” customers.

Fishbone diagram sample—use of a cause/effect, Ishikawa, fishbone diagram to derive constraints (C-TEPO and C-TANO)

Exhibit 5: Fishbone diagram sample—use of a cause/effect, Ishikawa, fishbone diagram to derive constraints (C-TEPO and C-TANO).

Parking Challenge

To Go” customers need immediate parking close to the restaurant for quick service. However, dine-in customers also desire to park as close to the restaurant as possible. Especially during inclement weather and on busy nights, they want to park in the closer “To Go” reserved parking spots. Certainly, the restaurant does not want to offend or anger their higher revenue-per-person dine-in customers; yet it does not want to lose the extra revenue from the faster turn-over of “To Go” customers. In addition, if “To Go” customers cannot find parking close to the side door, they may wait in a traffic aisle and block the parking lanes, causing an unsafe environment for the server and other customers. Some inconvenienced customers will become dissatisfied and not return.

C-TEPO Solves the Parking Challenge

One restaurant chain team apparently had a creative brainstorm session and designed innovative signage to ensure a positive outcome of open parking spaces for their “To Go” customers. By the side door and with spot lights shining on these parking spaces, they posted their brand name at the top of their parking signs in big red letters on a white reflective background: “TO GO PARKING ONLY – 10 minute limit.” Next line: “All others will be CRUSHED AND MELTED” (see Exhibit 3). Obviously, they injected harmless, but clever humor, by suggesting an improbable and funny image, in the dine-in customer's mind that their vehicle would be crushed and melted if they parked in these reserved spots. Management kept the good will of dine-in and “To Go” customers with planning, technology, humor, and effective communication, saving these parking spaces exclusively for “To Go” service (see entries C and D in Exhibit 6).

C-TANO prevents a tragic event: Diagram entries for C-TANO (see bottom half of Exhibit 5) that avoid the negative outcome of a “Robbery of Server” are mapped to the (E) entries found in Exhibit 6. Resulting constraints (column 6) require the server to carry no cash except from one customer at a time, or the change from the cashier. The new construction design required a well-lighted parking and door area, security cameras with warning signs, and electronic door locks controlled by the cashier or server. (Nonsafety related Constraints are shown in F entries.)


In this paper, project constraint management and a new project management category of constraints were defined. A columnar-form template, tools, methodology, and examples were offered so that project managers can apply these positive concepts and creative approaches quickly and easily to new projects to ensure successful outcomes. (Templates and additional information may be freely downloaded from the author's website:

By definition, risks are not constraints. Project managers must analyze to assure their Projects will be successful, to produce tangible and/or intangible benefits, and to increase the value of their project management.


Goldratt, E. (1999). The theory of constraints. Great Barrington, MA: North River Press Publishing.

Kozy, K. R. (2008). Constraints to avoid negative outcomes--a proposal for a new useful category of PM constraints that was discovered while analyzing a project completed 20 centuries ago. PMI Global Congress 2008—Asia Pacific. Newtown Square, PA: Project Management Institute. [Electronic Version] Retrieved December 22, 2008, from PMI website:

Kozy, K. R. (2009). Project Management Constraint Template. [Electronic Version] Retrieved November 3, 2009, from Web-site:

Liker, J. K. (2004). The Toyota way: 14 management principles from the world's greatest manufacturer. New York: McGraw-Hill.

Project Management Institute. (2004). Practice standard for earned value management. Newtown Square, PA: Author.

Project Management Institute. (2006). PMI code of ethics and professional conduct. Newtown Square, PA: Author.

Project Management Institute. (2008). A guide to the project management body of knowledge (PMBOK® Guide)—Fourth edition. Newtown Square, PA: Author.

Thomas, J., & Mulley, M. (2008). Researching the value of project management. Newtown Square, PA: Project Management Institute.

Project management constraints – identifying outcomes and constraints (“To Go” restaurant service example)

Exhibit 6: Project management constraints – identifying outcomes and constraints (“To Go” restaurant service example).

© 2010, Kenneth Kozy
Originally published as part of the 2010 PMI Global Congress Proceedings – Melbourne, Australia



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