November 14, 2018 | Chris Vallee

Can You find A Deviation, Defect, or Quality Escape Causal Factor?

Hint, there is usually more than one Causal Factor that:

  • caused the deviation/defect
  • failed to catch/stop the deviation/defect
  • failed to mitigate the quality escape when the deviation/defect reached the internal/external customer.

Let’s start with a few definitions.

Quality Escape: Any product/service released by an internal or external supplier or sub-tier supplier that is subsequently determined to be nonconforming to contract and/or product specification requirements. Definition Reference

Important Question: Is it a quality escape if the product or service met design/customer specifications?

Defect:  Non-conformance of a product/service with the specified requirements, or non-fulfillment of user expectations (including the safety aspects).

Shortcoming that prevents an item from being complete, desirable, effective, safe, or of merit, or makes it to malfunction or fail in its purpose. Definition Reference

Important Questions: Is it a defect if made to specifications?

If the defect is corrected on the spot would you analyze for Causal Factors or Root Causes?

Causal Factor: A mistake, error, or failure that directly leads to (or causes) an Incident, or fails to mitigate the consequences of the original error.

  • An Action someone performed?
  • An Action a piece of equipment, component or process transaction performed?
  • An Action not performed by someone?
  • An Action not performed by piece of equipment, component or process transaction?

Important Note: We do not fix Causal Factors, we fix Root Causes that allowed, encouraged or failed to prevent the Causal Factor from happening.

Root Cause: The absence of a best practice or the failure to apply knowledge that would have prevented the problem (Causal Factor), or significantly reduced its likelihood or consequences.

Back to finding Causal Factors. As stated earlier, there is usually more than one Causal Factor that caused the defect, failed to catch/stop the defect or failed to mitigate the quality escape when the defect reached the customer. Experts are often quick at finding the Causal Factor for the defect. What is often missed are Causal Factors that:

  1. Failed to catch/stop the defect
  2. Failed to mitigate the quality escape

Let’s stop and think for a second, how many source inspections, in process inspections, no-go mistake proofing safeguards and eyes on and touch points do companies have built into most of their quality systems? How on earth could failures to catch a defect or allow a “defect” to escape forward to the next customer?

Here are some common failure points to discuss:

  1. Does the assembler or inspector have working knowledge of how their task completion point fits into the final product or service to the customer?

For example, an assembler drills an alignment hole into a sub-assembly per blue print and the inspector stamps the part off as per specification. The part is forwarded to final assembly. The final assembler uses the alignment hole to drill a hole in the final assembly and drills into another component, damaging it.

Would you have identified the part being passed per specification as a Causal Factor? You should, because this is a touch point that could have prevented and internal quality escape.

  1. The damage to a part that creates a repair or rework is assigned as the cause of the defect as opposed to just treating it as a point of discovery that needs to be investigated. Often, this encourages an unauthorized correction to “make it work”.

In the example above to prevent future quality rework requiring quality notifications, final assemblers moved the part over slightly to ensure that it would not be drilled into while drilling through the alignment hole. This again would be another Causal Factor to be analyzed for root causes.

These are just a few ideas to get your mind in gear to finding accurate Causal Factors to then be analyzed for effective Root Causes to prevent future Quality Escapes.

Learn more about identifying Causal Factors in our 2-Day TapRooT® Essentials Course.

Categories
Quality, Root Cause Analysis, Root Cause Analysis Tips
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