Late on a Friday afternoon, the detective sits beside a customer service team in a retail distribution company.
The same issue has come through again. An order went out wrong. A customer has called back. The team apologises, corrects it, logs the complaint, and moves on. Then the same type of error appears again next week. And the week after that. Nobody is surprised anymore.Â
At first glance, it looks like a few isolated mistakes. But the detective knows better. This is Defects, one of the 8 wastes in Lean, where outputs do not meet requirements and have to be corrected, redone, or apologised for.
If you’re new to the 8 wastes, this case links back to the bigger picture explored in our original blog post here.
The Scene: When Errors Keep Returning
In many organisations, defects show up as small frustrations at first.
A form is completed incorrectly. An invoice needs correcting. A delivery goes to the wrong address. A report goes out with the wrong number in it. One mistake might be brushed off as a one-off. But when the same error keeps returning, it is no longer just a mistake. It is a signal.
The problem with defects is that they do not stay contained. They create rework, delays, complaints and extra checks. They consume time that should have been spent moving work forward. And often, they reveal a process that is not quite doing what it is supposed to do.
The mistake is usually visible. The cause is usually hidden.
Clues: Where to Look for Defects
Defective waste appears wherever outputs fail to meet the required standard and have to be fixed after the fact. It often hides in repeat issues that have become normalised.
You are likely to see it in places like these:
- Errors in orders, invoices, or data that need correcting later.
- Products or outputs that fail quality checks and must be reworked or scrapped.
- Customer complaints that keep pointing to the same step in a process.
- Information passed between teams that is regularly wrong, missing, or incomplete.
- Decisions made on inaccurate data, leading to actions that later need reversing.
Anywhere a process creates extra work because something was wrong the first time round, defects may be present.
Interrogation Questions: How to Spot It in Your Process
To uncover defects, ask questions that trace the error back to its source.
- What are the top recurring error types and do we know exactly where in the process they originate?
- How much time is being spent on rework and correction?
- Is the root cause being investigated, or are we just adapting around the problem?
- What is the true cost of our defect rate, including staff time, materials, and reputation?
These questions help move the focus from fixing symptoms to fixing causes.
The Verdict: What’s Really Going On
Defects are expensive because they reveal a process failure, not just a one-off mistake.
It is easy to blame the latest error, the latest customer complaint, or the latest wrong form. But the real issue is usually deeper: a process that allows the same problem to happen again and again. When that happens, organisations start carrying the cost of their own preventable failures.
The endless loop is the warning sign. If the same defect keeps returning, the process is telling you something important. And ignoring it does not make it cheaper.
And once you start seeing defects for what they are, the trail does not end here. The final case on the file is waiting: Case #008: The Case of the Untapped Potential.