Developing a Process Audit Plan

1. The "Policing Process": Why Audits are Essential for Control

After implementing improvements and documenting them in SOPs, the project enters a new stage. The focus shifts from change to sustainment. A process audit is the primary tool for this. Think of it as a "policing process" designed to check that the new rules are being followed.

Let's watch a short clip that frames the role of audits within the Control phase of a Six Sigma project.

As the video highlights, the control system is inextricably linked to the improvements you've made. An audit plan formalizes this link, creating a structured way to verify that your new SOPs, control chart reaction plans, and mistake-proofing devices are all being used as intended. Without this verification step, processes naturally revert to old habits, and the project's hard-won gains will erode over time.

2. A Structured Approach: Layered Process Audits (LPAs)

One of the most effective ways to structure process audits in a manufacturing environment is the Layered Process Audit (LPA) system. Instead of relying solely on the Quality department, an LPA involves multiple "layers" of the organization—from team leads to plant managers—conducting short, frequent audits.

This approach has several key benefits:

• Drives Management Engagement: It gets leaders out of their offices and onto the shop floor, showing commitment to the standards.
• Fosters a Culture of Accountability: Everyone becomes responsible for upholding process discipline.
• Provides Rapid Feedback: Frequent checks catch deviations before they can lead to significant quality issues.

To understand the framework, let's look at a real-world procedure.

The core idea is simple but powerful: different levels of management audit the same core processes, but at different frequencies. This creates overlapping layers of verification.

3. Building Your Process Audit Plan: The Key Components

A robust audit plan must clearly define four things: Who conducts the audit, What they will check, When they will check it, and How the audit is performed and followed up on. LPAs provide an excellent structure for defining these elements.

a) WHO: Defining the Layers and Responsibilities

An LPA distributes auditing responsibility across the organizational hierarchy. Each layer has a distinct role and frequency.

A typical structure looks like this:

• Layer 1: Team Leader/Operator: Daily or per-shift checks of their own area. Focus is on critical-to-quality items and adherence to SOPs.
• Layer 2: Supervisor: Weekly audits. Broader scope, verifying Layer 1 audits are happening and checking on corrective actions.
• Layer 3: Manager/Department Head: Monthly audits. Focus on the health of the system, trend analysis, and systemic issues.
• Layer 4: Plant Manager/Executive: Quarterly audits. High-level check to ensure the entire LPA system is functioning and aligned with business goals.

b) WHAT: The Audit Checklist

The checklist is the heart of the audit. It translates your Control Plan and SOPs into a series of specific, objective questions. A weak checklist leads to a weak audit.

Tips for Creating an Effective Checklist:

• Be Specific and Objective: Questions should be yes/no or based on direct observation. Avoid subjective questions like "Is the area clean?" Instead, use "Are tools stored in their designated locations on the shadow board?"
• Focus on High-Risk Items: Prioritize questions related to your project's CTQs, key process variables from your FMEA, and safety requirements.
• Link to Standards: Every question should trace back to a requirement in an SOP, Control Plan, or engineering specification.

The Nexteer procedure includes an excellent, detailed example of what to include in a checklist.

Here is another example of a well-structured LPA checklist for a welding process.

c) WHEN: The Audit Schedule

The schedule ensures consistency and full coverage of all critical processes over time. It visually maps out who is responsible for auditing which area and at what frequency.

The Nexteer document provides a simple but effective template for an audit schedule. The key is to make it visible and easy to track. Many plants use large, physical boards at the production line for this purpose.

d) HOW: Conducting the Audit & Closing the Loop

With the plan in place, the final component is the execution. The audit itself is an active process of going to the gemba (the actual place where work is done), observing the process, talking to the operator, and verifying against the checklist.

This video provides a superb practical demonstration of an auditor on the shop floor. It perfectly illustrates what a process audit aims to uncover.

The video brilliantly demonstrates the most critical part of the audit process: identifying the gap between the documented process and the actual process.

Once a non-conformance is found, the loop must be closed.

1. Immediate Containment: If there's a risk to quality, take immediate action to contain suspect products.
2. On-the-Spot Correction: If possible, the issue should be corrected immediately (e.g., retrieving the correct tool, reminding the operator of the standard). This is often done by the Layer 1 or 2 auditor.
3. Formal Corrective Action: For recurring or systemic issues, a formal corrective action plan is needed to address the root cause. This is a key input for continuous improvement. The LPA board in the image above has a dedicated section for tracking these actions.

4. Bringing It All Together: Your Audit Plan

To summarize, developing a process audit plan involves these key steps, adapted from the L2L article Layered Process Audits: Framework, Steps, and Frontline Impact:

1. Define Objectives: What is the primary goal? (e.g., ensure compliance with new SOP for process XYZ, reduce defect ABC).
2. Build the Audit Team/Structure: Define the layers (Who) and their audit frequencies (When).
3. Develop Checklists: Create specific, objective checklists based on Control Plans and SOPs (What).
4. Establish the Schedule: Create a visual schedule to track completion.
5. Define the Follow-up Process: Determine the reaction plan for non-conformities (How).
6. Train the Auditors: Ensure everyone from the operator to the plant manager understands their role and how to use the checklist.
7. Launch and Monitor: Execute the plan and track results (e.g., audit completion rate, first-time pass rate of audits).

Conclusion

In this lesson, we have constructed a complete framework for ensuring your project's improvements are sustained over the long term. You've learned that a process audit plan is not an administrative burden but a dynamic management system that drives compliance and continuous improvement.

Key Takeaways:

• Purpose: A process audit plan is a formal system to verify that standards (like SOPs) are being followed and that process gains are maintained.
• LPA Framework: Layered Process Audits are a highly effective method that involves multiple levels of management in conducting frequent, short audits.
• Key Components: A strong plan clearly defines the Who (layers), What (checklist), When (schedule), and How (execution and follow-up).
• Closing the Loop: The goal of an audit is to identify deviations and trigger corrective action, feeding back into a cycle of continuous improvement.

Preview of the Next Lesson:

We are now nearing the end of the Control phase and the project itself. We have improved the process, created standards, and built a plan to ensure those standards are followed. The final step in project closure is to quantify the project's success. In our next lesson, we will learn how to calculate the financial impact of the project, differentiating between hard and soft savings. This will allow you to present a complete and compelling story of your project's value to leadership.