by Thomas A. Gray
Layered process audits (LPAs) have become very popular lately. Their popularity is a result of mandatory requirements from the automotive industry as well as a desire from customers for organizations to ship correct products that meet all customer requirements, correctly labeled, all the time.
LPAs can be used to meet the requirement for manufacturing process audits in paragraph 126.96.36.199 of ISO/TS 16949. They can also be used as a preventive action and/or continual improvement technique within the internal audit system for other quality management systems (QMS) standards, such as ISO 9001, AS9100, and ISO 13485. As with all quality tools, don’t implement LPAs simply to meet a customer requirement or satisfy a QMS requirement. Instead, use LPAs to prevent errors and drive continual improvement within the organization. The following is a step-by-step guide to structure and implement an LPA approach to drive continual improvement.
Step 1: Create an LPA implementation team
An excellent starting point for LPA implementation is a management objective or action item decided during a formal management meeting, preferably a management review. Once the action item is formalized, the management team can begin discussing resources necessary for the LPA system and assign an LPA implementation team. It can then be tracked as the action item is reviewed at subsequent management review meetings.
The LPA implementation team will:
- Learn about the LPA process, including best practices
- Decide how the facility will be audited (value stream, process, product group, etc.)
- Decide the number of layers in the organization’s LPA approach and who will participate within each layer
- Prioritize the LPA roll-out to the areas, processes, and/or products that will be part of the system
- Create LPA checklists for each layer of the audit
- Train employees that will be LPA auditors
- Review layered audits and results to make corrections to the LPA process
- Compile LPA metrics to show the effectiveness and efficiency of the LPA system for management review
The LPA implementation team should be cross-functional. Its members should be team players who want to gain positive results from the LPA system. This isn’t a cross-functional team where you want to have a skeptic on board so that you can convert him or her. Try to gain representation from all of the areas of the organization, including engineering, manufacturing, maintenance, quality, office, etc. A representative from the manufacturing function should own the LPA process and lead the LPA implementation team. Someone from the quality department should support the manufacturing representative.
Step 2: Decide how the facility will be divided for auditing and prioritize each area
After learning about the LPA process, the LPA implementation team should create a road map for the LPA implementation. The first piece of this road map is the identification of all of the primary and secondary organizational units of the company. Depending on how the company is divided, primary organizational units are typically grouped as business units, value streams, or departments. Secondary organizational units are typically called work stations, cells, or operations. In addition, the LPA implementation team should list product groupings or product families that flow through these organizational units. A typical spreadsheet from a company would look like table 1.
Table 1: LPA implementation: LPA organizational structure
|Primary (Business)||Secondary (Operation)||Product Grouping|
|GM dashboard||Molding||GM Part No. 1 & 2|
|Water jet||GM Part No. 1 only|
|Packing & shipping||GM Part No. 1 & 2|
|GM side panel||Molding||GM Part No. A – D|
|Packing & shipping|
After the spreadsheet is completed, the LPA implementation team should prioritize the primary and secondary organizational units for their order of implementation. To determine the priority of the areas to be audited, the LPA implementation team should:
- Consider processes and areas that have a known, unacceptable variation
- Review quality tools, such as failure mode and effects analyses (FMEA) to look for processes with high risk priority numbers (RPN)
- Review quality information for processes with high incidents of error
- Review corrective actions—including customer complaints—for processes where actions have recently been implemented to prevent the recurrence of an error
Processes in which there is a high incidence of error or a high risk of error are perfect for the initial round of implementation. Typically, as the team implements the LPA process, LPA checklists are made for each of the secondary operations. Metrics can then be organized by each of the secondary operation steps and either aggregated to the primary unit as an overall report or drilled down to the product grouping to determine specific areas in need of improvement.
Step 3: Decide the number of audit layers and their audit frequency
LPA systems must have at least two layers of auditors, though some typical systems have between three to five layers of auditors. The different layers of auditors complete the same audits with the same set of standard questions. Table 2 lists typical audit layers and frequencies of audits and auditors.
Table 2: LPA implementation: LPA system audit layers
|Audit layer||Audit frequency||Auditor|
|Layer 1||Each shift, every day||Typically operator or technicianCan be supervisor and/or maintenance personnel|
|Layer 2||One to two audits per week||Typically area managers or supervisorsCan be engineers and/or quality personnel|
|Layer 3||One audit per week||Typically managers, such as plant manager, engineering manager, quality manager, etc.|
|Layer 4 & higher||One audit per week, month, or quarter||Typically senior managers*|
* For Layer 4 or higher, the organization should understand the value in the use of the auditor’s time in performing the LPA.
Layer 1 audits must be performed after each shift. The auditors for layer 1 audits are typically direct employees to the process, but may also include support functions such as maintenance personnel and quality inspectors. The focus of a layer 1 LPA is to verify that the critical parameters for the process are being performed without variation. If there are more layer 1 auditors than processes in the area, consider rotating the responsibility of the LPA to give all auditors the opportunity to perform the audit.
The LPA implementation team determines the frequency for the audits in layers 2 and higher. Table 2 shows typical audit frequencies for each of these layers. The auditors for layer 2 are usually the area supervisors or managers, but may also include manufacturing engineers or quality engineers. In layers 2 and higher, the auditor’s focus is to
- Gain knowledge about the process being audited.
- Ensure that the process is organized correctly and creating products that meet customer specifications.
- Determine if the lower-layer audits are being completed correctly or if they are being “pencil-whipped.”
- Communicate with the operators in a way that helps in creating process improvement.
For layers 3 and higher in an LPA system, the LPA implementation team will need to set clear expectations for the value that each additional audit layer will add. For example, in a flat organization, more than two audit layers may not be necessary, as there is less of a need to consciously create communication between the management team and the employees. On the other hand, if the LPA implementation team believes that audits will be “pencil-whipped,” it might include a layer 3 audit of managers with the intent of reviewing the effectiveness of the layer 1 and 2 audits.
Step 4: Create checklists for each of the audit layers
The LPA implementation team should develop checklists for each LPA. An LPA should take only 10–15 minutes to complete. Audit checklists for LPA should contain between less than ten questions, all of them “Yes/No.” A “yes” response means that the process or item is in control. A “no” response means that the process or item is not in control and that corrective action must be taken. The LPA implementation team should use the same information that it used to prioritize the areas to be audited (known variation, RPN, corrective actions, etc.) to create the audit questions.
Typically, the audit checklist is the same for the area for each layer of the LPA, although the implementation team may create additional questions for layer 3 and higher to look at broader areas, such as 5S effectiveness.
A best practice in creating checklist questions is the “what/how/why” approach. For this approach, the team crafts the “what” portion of the question for the “yes/no” response. The “how” portion of the question gives the auditor information on what to review to determine that the checklist question is in control. The “why” portion of the question gives the auditor the reasoning behind why the question is important to the company and its customer. To show the different parts of the question, different font choices (i.e., bold, italics, etc.) can be used. Bold can be used for the “what” part, normal font can be used for the “how,” and italics can be used for the “why.” By using this approach, the LPA implementation team can cull the list of questions for a 10–15 minute audit based on the importance of the question. A typical LPA checklist question is listed in figure 1.
Figure 1: LPA implementation: Typical LPA checklist question
|Typical Layered Process Audit Checklist Question (What/How/Why)|
|Correct Product Label is Applied to Correct Area on Shipping Container? Check part number on traveler with label in database against label applied to the container. Improper labeling may cause customer errors in process, causing customer dissatisfaction and potentially charges.|
Finally, the checklist must include a section for corrective action information if the audit shows that the item is not in control. For the question listed in figure 1, if the part number on the label is incorrect, the checklist should show what corrective action—such as reprinted and re-applied labels to containers and reviewed stock for further mislabeled containers—was taken. The LPA approach allows prior corrective action information to be immediately obvious.
Step 5: Train the auditors
Formal training for LPA auditors is different than for QMS auditors. Because many LPA auditors either directly work within the process or support the process being audited, they have an intimate knowledge of it. Training for these auditors should consist of:
- An overview of the LPA system and its importance to the organization
- A sample of the checklist that will be used at each layer of the LPA
- A mock audit of the area using the checklist, including filling out its corrective action portion
- A discussion of corrective actions to be taken for a “no” answer, including who to contact when corrective action is necessary
The LPA implementation team must ensure that all of the auditors are comfortable with how to both audit the items on the checklist and know what to do when corrective action is required. A lack of evidence of a direct link between a “no” answer and corrective action indicates that the audit has simply been pencil-whipped and shoved under a carpet somewhere.
Step 6: Follow through
Set up an audit schedule, including scheduling auditors for each level, and follow through with it. The LPA implementation team should review the LPAs performed each day for the first week and for up to a month to gain feedback about how it’s working. When nonconformities are found and fixed, the LPA implementation team should celebrate the success of the LPA approach with the employees in that area. Over time, the team can back off from the daily review, but only when it has determined that the habit of performing LPAs has been successfully established.
Step 7: Collect metrics and report them at management review
There are two types of metrics that can be established for an LPA system. When first establishing an LPA approach, it’s important to ensure that the audits are being properly completed. Organizations typically measure the number of LPAs completed vs. the number of those scheduled. This metric is useful in making sure that the LPA system is becoming a habit within the organization, but it doesn’t show the effectiveness of the LPA system in preventing problems and/or driving improvement. After the management team has determined that the LPA system has grown roots in the organization, this measure should be discontinued.
The second type of measure can be based off of corrective actions. Trends in the number of issues per audit combined with a Pareto analysis of the type of issues raised can be reviewed. The data can be drilled down to specific processes and product groups to show whether particular operations and/or products have higher rates of incidents. The management team can combine this analysis with its review of scrap, rework, or cost of quality. An effective LPA system will show a positive effect on each of these measures and the management team should verify this effect during its management review.
Step 8: Adjust the LPA system
In the beginning, the management team and LPA implementation team should review the percentage of LPAs completed. Both teams are reviewing to see that the habits required to have a functioning LPA system have been established. If the percentage of completed LPAs is lower than the teams require, then corrective action should be taken. Typical corrective actions would be ongoing training of auditors and review and revision of audit checklists, etc.
As the LPA system matures, it’s not uncommon that the layered audits yield no corrective actions, but that the organization still contends with scrap, rework, and customer complaints in the process. When this happens, the LPA implementation team should get back together, review the data, and change the checklists for the LPAs to check for the areas that are currently creating the scrap, rework, and customer complaints. In this way, the organization is always reviewing the areas where the process is in need of ongoing supervision and control.
In conclusion, LPAs—when implemented successfully—can be used as a proactive tool to prevent problems and drive continual improvement. They enhance communication between employees from the front office to the production floor while creating and reinforcing habits that reduce variation in critical customer requirements.
About the author
Thomas A. Gray has a master’s and a bachelor’s degree in chemical engineering. He has extensive experience in quality and operations management, having worked 15 years supporting the automotive, aerospace, and health care industries. He has assisted numerous organizations gain compliance and/or certification to various quality management systems, including ISO 9001, ISO/TS 16949, AS9100, and ISO 13485. He has developed and implemented successful lean manufacturing programs for manufacturing and service organizations, including the implementation of manufacturing cells, cross-training of self-directed work teams, and deployment of kanban pull systems.
Gray is a facilitator, project manager, and designer of learning/training events. He has served on several local and national committees promoting the development of quality systems and best practices. In March 2002 he founded Productivity Improvement Network Inc., an organization dedicated to helping companies gain continual improvement through training and consulting services.
Tags: layered process audits, LPA implementation.