Quality Management in Projects: Common Mistakes
Quality management is one of the knowledge areas most teams claim to understand and most teams under-invest in. The gap between what project quality management is supposed to deliver and what it actually delivers in practice is often explained not by a lack of good intentions but by a cluster of predictable mistakes — mistakes that repeat across industries and project types.
The foundation is a distinction that is easy to state but frequently blurred in practice: quality assurance and quality control are not the same thing, and conflating them is where many projects go wrong.
QA vs QC: Not the Same Thing
Quality assurance (QA) is about the processes you put in place to prevent defects. It is proactive and process-focused. Quality control (QC) is about inspecting outputs to detect defects after they have occurred. It is reactive and product-focused. A project that invests only in QC — checking outputs at the end of each phase — will find defects, but it will find them late, when they are expensive to fix. QA investments, by contrast, reduce the rate at which defects are created in the first place.
The Cost of Quality Framework
The cost of quality (CoQ) model divides quality-related expenditure into three categories. Understanding these categories changes how a project manager thinks about the quality budget.
Prevention costs. Money spent to stop defects from occurring: training, process design, standards development, checklists, and upfront planning. These are typically the cheapest quality investments.
Appraisal costs. Money spent to detect defects: testing, inspections, audits, and reviews. These find problems but do not prevent them.
Failure costs. Money spent because defects occurred. Internal failures (rework, scrap) happen before delivery; external failures (warranty claims, client disputes, reputational damage) happen after. External failure costs are almost always the largest and most destructive category.
Most projects that struggle with quality are spending too much on failure costs and too little on prevention. Increasing the prevention budget — even modestly — typically produces a disproportionate reduction in failure costs, because fewer defects enter the system.
Common Mistakes and How to Fix Them
Confusing QA with testing. Testing is a QC activity. Many teams think they have quality assurance because they test thoroughly. Assurance means auditing whether your processes are designed correctly and being followed — not just checking what they produce. Fix: schedule process audits separately from deliverable reviews.
Not defining quality criteria upfront. A project cannot measure quality against undefined requirements. When acceptance criteria are vague or absent, teams default to "looks good to me" — which produces disputes at handover. Fix: make measurable acceptance criteria a condition of baseline approval for every deliverable.
Treating quality as a phase, not a continuous activity. Quality reviews that appear only at phase gates miss defects introduced in the middle of phases, where they compound. Fix: integrate short quality checkpoints within phases, not only at their boundaries.
Ignoring non-conformance data. When defects are found, teams fix them and move on. The data about what broke, where, and why is rarely captured systematically. Fix: log every non-conformance in a register with root cause, not just a symptom. Review the register at each retrospective.
Bolting quality on at the end. This is the most expensive mistake. Quality added as a final step finds problems when they are most costly and time-consuming to resolve. Fix: involve QA thinking in design, not just verification. Ask "how will we know this is right?" at the start of every work package.
The practical shift is from thinking of quality as a set of checkboxes to thinking of it as evidence that your process is working. A project with good quality management produces fewer surprises at handover not because it inspected more, but because it was designed to surface problems early and continuously.
XNM Consulting integrates quality management into project delivery frameworks across infrastructure, technology, and public-sector programs. See our Program and Project Delivery page for more.