Fix the Cause, Not the Symptom: Three Quality Habits, Side by Side

Symptom or cause?

Treating the symptom means dealing with what already happened: sort out the bad parts, patch the leak, replace the person who made the mistake. Fixing the cause means going back to what made it happen. You will do both. You don't have to stop firefighting, but if that is all you do, the same problem keeps coming back.

Inspecting vs preventing the defect

However hard you sort, the line keeps making bad parts, because inspection can find defects but cannot stop them from happening. Error-proofing (poka-yoke) works where the part is made: a part loaded the wrong way will not fit, or the process stops as soon as something goes wrong. The mistake simply can't be made.

Start here: pick the defect you sort out most often, and ask whether it could be stopped at the station where it happens.

Patching symptoms vs fixing the root cause

A pipe leaks, so someone wraps it in tape, and a few days later it leaks again next to the tape. Tape buys a little quiet, but the cause of the leak is still there. Fixing the cause means following the pipe back, finding the one worn valve and replacing it. Only then does the pressure settle.

There are many ways to trace a cause back. A common one is 5 Why: ask "why" several times in a row until you reach a cause you can act on. For a fuller approach, use a step-by-step problem-solving method such as 8D. See also how to judge whether a supplier 8D actually worked.

Start here: before you write the next corrective action, check whether it names a cause or a symptom.

Blaming operators vs improving the process

Something goes wrong, and a supervisor takes a sheet covered in red crosses to the operator. Replace the person, and some time later someone else makes the same mistake.

Improving the process means the team works out together where the process makes errors easy, such as an unclear standard, a parameter that is not locked, or a check placed at the wrong step, and then fixes it. What often happens is that a "human error" turns out to be a process that made the error easy to make.

Start here: before you write "human error" as the root cause, ask one more time why the person did what they did.

What the three have in common

The difference between each pair is not who works harder. It is where the effort goes. Firefighting is hard work, and the problem still comes back. Deal with the cause, and you won't have to fight the same fire again.