Back to ArticlesBack

Join 50,000+ PM Professionals

Get expert PM insights, PMP prep tips, and earn PDUs with exclusive content delivered weekly.

Protected by reCAPTCHA: Privacy & Terms

MPUG - Master Project User GroupMPUG - Master Project User Group

Introduction

Most courses and books on project management discuss the “Triple Constraints” in terms of a three-legged stool (see Figure 1 below). The first leg represents Scope Management, the second, Time Management, and the third, Cost Management. If one aspect is shortened or increased in length, then the two other “legs” must be adjusted accordingly for a successful project. For example, if you increase scope, it will influence time and cost. Balancing the triple constraints is a lot like juggling. It’s also a constant reminder of how changing one constraint will cast an impact on the entire project.

Figure 1: Three-Legged Stool

I have been working in project management for over four decades, and I’ve have observed at least two dozen projects that met the scope, cost, and time goals without being considered successful by the sponsor/customer. Why? There are many factors (resources, communications, procurement, risk, and quality are a few) that can lead to this situation, but most of the time, it was the lack of quality being “baked” into the final service or product. Some people, including myself, believe the triple constraints should be expanded into quadruple constraints, including quality with the aspects of scope, time, and cost. The bottom line is having and meeting quality standards is a key factor in obtaining customer or sponsor satisfaction. It’s likely that this desire for quality was the primary reason why the project was undertaken, in the first place, so why shouldn’t it be just as important as time, scope, and cost?!

Quality Management

One of the principles of quality management (QM) is that it’s customer oriented. It’s also made up of two key parts: quality assurance (QA) and quality control (QC). QA is the maintenance of a chosen level of quality in a service or product, especially by means of attention to every stage of the process of delivery. The goal here is to meet the needs and expectations of the customers. This all helps to build trust and loyalty. QC involves inspections, reviews, and evaluations of the various units to determine if they are within the specifications for the final product. This is accomplished through independence, integrity, and objectivity. QA is process oriented, whereas QC is product oriented. Projects should have periodic mini reviews that rate progress against certain defined metrics. Table 1 combines the three types of QM reviews (health, compliance, and deliverable) into one mini review.

Table 1: Mini QM Review

Every project should have prescribed quality indicators that can be used for recovery assessment. This includes the level of defects or number of discrepancies in deliverables–first by internal review, and then by the customer. We also want to look at the number of re-work activities following internal and customer reviews. Monitoring all of this on an ongoing basis is essentially part of tracking and controlling project performance.

For software development projects, make sure the end-users or customers are part of the participative development team, so they feel they have ownership of the service or product (this should increase their overall satisfaction). Expect the product requirements to evolve throughout the development process, and continue to validate that the proposed product will be satisfactory to the customer after it is completed and delivered.

Summary

Always try to see quality through the customer’s eyes, and remember it applies to the life of a product and covers all aspects of a product. I have seen several products introduced that had great quality, but the price was unbelievably high because they had a near monopoly on the marketplace. When the product starts to have competition, prices are lowered and companies look to cutting costs to keep profit margins up. This can result in the product’s quality being reduced. I am speculating a possible example of this is Gillette, which once held a 70% market share in US for razor blades. We’ve seen upstarts like Harry’s and Dollar Shave Club (DSC) slice away at Gillette’s customer base over the last decade. While Gillette remains in control, its market share has shrunk down to nearly 50%. A possible lesson to be learned is that if your product is overpriced and/or you ease up your interest in ensuring quality to save costs, your competitors will gladly demonstrate their interest in winning over your customers.

Your thoughts on expanding the triple constraints into the quadruple constraints of project management in the comment section below are appreciated.

Get Weekly PM Insights

Join 50,000+ PMs receiving updates on the latest PM methodologies, PDU opportunities, tool reviews, career tips, and member exclusives.

Protected by reCAPTCHA: Privacy & Terms

PMI ATP
PMI Authorized Training Partner
REP #4082

Learning Paths

PMP® TrainingCAPM® TrainingPgMP® TrainingPMI-ACP® TrainingMS ProjectMS PlannerMS TeamsJira

PM Resources

PDU TrackerLive WebinarsSalary CalculatorTool ComparisonsJob BoardKnowledge BasePM Glossary

Community

Discussion ForumStudy GroupsEvents Calendar

Follow Us

LinkedInYouTubeTwitterFacebook
MPUG Logo

© 2026 MPUG. All rights reserved.

TermsPrivacySitemapAdvertise
Articles

The Quadruple Constraints of Project Management

Most courses and books on project management discuss the “Triple Constraints” in terms of a three-legged stool (see Figure 1 below). The first leg represents Scope Management, the second, Time […]

4 min read
•almost 4 years ago•Updated about 2 months ago•
R
Ronald B. Smith, MBA, PMPAuthor
Project Management
Microsoft Project
Best Practices
Productivity
R
Ronald B. Smith, MBA, PMP

Content Writer

Ronald Smith has over four decades of experience as Senior PM/Program Manager. He retired from IBM having written four books and over one hundred articles on project management, and the systems development life cycle (SDLC). He’s been a member of the Project Management Institute (PMI) since 1998, which has a membership of about 3 million professionals worldwide. From 2011 - 2017, Ronald had been an Adjunct Professor for a Master of Science in Technology and taught PM courses at the University of Houston’s College of Technology. Teaching from his own book, Project Management Tools and Techniques – A Practical Guide, Ronald offers a unique perspective on project management that reflects his many years of experience. Besides writing, he swims five times a week to keep in shape. Lastly in the Houston area, he has started up two Toastmasters clubs and does voluntary work at various food banks to help people facing hunger.

View all articles by Ronald B. Smith, MBA, PMP
Related Content

Continue Reading

Discover more insights and articles that complement your current reading

Your Project Online Migration Questions, Answered: Key Takeaways from Ira Brown
Articles
1 min read

Your Project Online Migration Questions, Answered: Key Takeaways from Ira Brown

Ira Brown, president of Project Widgets, breaks down the four realistic migration paths, key deadlines, and a pre-migration inventory checklist to help your organization plan ahead of the September 2026 Project Online retirement.

A
Anonymous
12 days ago
Read
The Compass vs. The Clock: Why Direction Beats Deadlines in Project Management
Articles
1 min read

The Compass vs. The Clock: Why Direction Beats Deadlines in Project Management

Discover why setting clear project direction matters more than chasing deadlines, and how compass-guided leadership delivers real value in project management.

A
Anonymous
23 days ago
Read
The Scripts That Save Projects: What to Say When Everything Goes Wrong
Articles
1 min read

The Scripts That Save Projects: What to Say When Everything Goes Wrong

Learn word-for-word scripts for handling scope creep, missed deadlines, executive pushback, and team performance issues as a project manager.

A
Anonymous
24 days ago
Read
Explore All Articles