The Fishbone that solved a $100,000+ problem!
What’s your go-to tool for cutting through complexity?
The right question costs nothing. The wrong answer can cost a fortune.
As a company leader, a recurring defect was draining thousands every month. Everyone had a theory, and I was responsible for resolving the issue. Initially, we used only the 5-Whys and kept on seeing the issue.
Eventually, I led a cross-functional workshop and used a Fishbone Diagram (With an interrelationship diagram and 5-Whys). Within 90 minutes, we traced the (originally missed) root cause to a faulty design that could be changed and revalidated.
Problem solved!
A 5-Why that stops at “operator error” will not survive an ISO 13485 or 21 CFR 820 design-control review. The fishbone forced the group to look at design, which could be changed and revalidated — the same sequence as a CAPA that actually closes.
Why 5-Whys stall in regulated plants
Five Whys is fast, which is why teams reach for it on the floor. It is also linear. Recurring defects in assembly, coating, or lab methods are usually several causes at once: a drawing that can be misread, a fixture that drifts, a training record that says “read and understood.” A single chain of “why” will pick the most convenient cause — almost always the person closest to the product. That is how you get retraining as a CAPA and a repeat finding six months later. See the broken CAPA case study.
Use the diagram, then revalidate
The workshop only paid off because the output was a design change that went back through verification. In a device QMS that is 21 CFR 820 / ISO 13485 design control; in a lab it is method revalidation under ISO 17025. A fishbone that dies in a conference-room photo is not a record. Attach it to the CAPA, name the cause category (design, method, machine, material, environment, measurement), and write the effectiveness check before you close. Assessments are often where we find the 5-Why habit in the first place.
One of my top Lean influencers, Karen Martin of TKMG, Inc., wrote in Clarity First:
"Ambiguity causes people to reach inaccurate conclusions, make faulty decisions, or spin their wheels in nonproductive ways. The absence of clarity also creates an opportunity for biases and assumptions to influence how people interpret information. ... Ambiguity prevents organizations from operating with focus, discipline, and engagement."