Consider the last time you conducted a layered process audit. What did you learn? How much insight did you get to improve the process? Did you have the opportunity for coaching and feedback?

If the answer to any of these questions was “not much,” then you’ve got work to do on your layered process audit checklists.

Layered process audits (LPAs) are a type of high-frequency audit common in automotive and aerospace manufacturing. The audits take place multiple times daily and require participation from all levels of the organization, creating a series of checks to catch process errors before they become defects.

Avoiding Common Layered Process Audit Checklist Mistakes

Many people struggle when it comes to making checklists, which are the foundation for success with LPAs. Let’s look at some of the most common mistakes and how to avoid them. 

1. Questions Don’t Add Value

Arguably the biggest mistake people make with LPA checklists is including throwaway questions that add no value.

For example, you’ll see questions like, “Are the work instructions posted?” While this may seem important, it doesn’t really get to the root of defects in terms of deviating from the standard.

A better question would be, “Can the operator explain each step of the posted work instructions?” This question gets to the heart of the issue and gives you the chance to make suggestions (or find out why the standard doesn’t work for operators).

2. Only the Quality Department Writes Checklists

If your quality department is exclusively responsible for writing LPA questions, that’s a significant weakness. Quality people don’t always know processes well enough to pinpoint problems that lead to defects.

Instead, quality should collaborate with operations to write questions, with neither team having veto power over the other. This protects the integrity of questions. You’ll also want to get input from management, since they can often provide high-level insight.

3. Using Words Like “Correctly” and “Properly”

It’s common to see LPA questions that use subjective terms like “correctly” or “properly,” which requires the auditor to know exactly what is correct or proper.

Always remember, however, that auditors will come from all levels and departments, and thus may not automatically know what’s correct. But that isn’t a bad thing—in fact, getting those fresh eyes on your processes is the whole point of LPAs.

Do you think the guy in finance will know whether a specific gauge is calibrated correctly? Probably not. LPA questions must be more concrete, so you want to clearly state any specifications, tolerances or readings to be verified during the audit.

4. Only Experts Understand the Questions

To the point above about creating cross-functional teams of auditors, you want to make sure that people unfamiliar with any given process can answer questions easily. This also helps to avoid pencil-whipping, which can be detrimental to the accuracy of your reports.

Specificity goes a long way towards making questions more digestible. You can also make questions simpler by:

• Using fewer words whenever possible
• Looking at questions from an outside perspective
• Writing yes or no questions, with “yes” indicating pass and “no” triggering additional follow-up

5. Checklists Have Too Many Questions

If you want your LPA implementation to succeed, you need to keep audits short and sweet. Otherwise, people will skip audits because they don’t have time to complete them. The result: lower completion rates, less data and more difficulty achieving your goals.

To hit the high frequency required for LPAs, each audit should only take about 10 minutes. That means you need to keep the checklist to roughly 10 questions, with each one simple enough to be verified in about a minute.

6. Questions and Checklists Are Out-of-Date

Stale LPA checklists and questions are a big problem for manufacturers, particularly those using LPAs just to satisfy a customer requirement.

For LPAs to actually reduce defects, complaints and quality costs, checklist development needs to be an iterative process. If a question has a 99% pass rate, are you really learning anything by asking it?

To keep checklists fresh, you want to periodically rotate in new questions based on:

• Process Failure Modes and Effects Analysis (PFMEA) results
• Customer complaints and internal defects
• Scrap reports
• Certification audit findings such as IATF 16949 and ISO 9001 non-conformities
• Corrective actions and results of root cause analysis

7. Using the Same Checklist for Multiple Work Areas

The final mistake to avoid with LPA checklists is using identical checklists for every work area or production cell. It’s not always a “check the box” philosophy that drives companies to make this mistake, of course. In many cases, it comes down to the sheer complexity of scheduling, managing and following up on a large volume of audits.

If you’re doing it all on paper, you’ll likely find it much harder to create customized checklists that reflect current and emerging risks. An automated LPA platform, on the other hand, allows you to create customized checklists with rotating and randomized questions.

More than just making questions and checklists stronger, you’ll be able to pinpoint which processes drive your biggest problems. It’s that information that equips you to make big-time quality improvements, giving you maximum value from your investment in LPAs.