The Humble Checklist: A Simple But Effective Defect Prevention Tool
In The Checklist Manifesto, best-selling author and surgeon, Dr. Atul Gawande, demonstrates the power and versatility of a simple checklist. Dr. Gawande's book shows how professionals in a wide variety of occupation - from surgeons in operating rooms to airline pilots landing a plane in an emergency - rely on checklists to prevent errors and ensure safe and successful outcomes.
So why can we not achieve similar results with checklists in manufacturing? After all, inspections are a required element of quality control in manufacturing, and checklists are the most common method of conducting final inspections.
We find that outside of Toyota, checklists are often poorly designed and not used correctly, resulting in defects escaping to the customer. Manufacturers therefore mistakenly assume that a checklist is an ineffective quality assurance tool.
It turns out, that a plain old checklist, if designed and implemented correctly, can be a very effective defect prevention tools.
Some Simple Rules for More Effective Checklists:
- When to use a checklist: A checklist is most effective if it is used at a point in the process where it can prevent a defect, rather than at a point where it can simply detect a defect. Therefore a great place to use a checklist is during production set-up. Do you have the right fixtures? Do the cutting tools need to be replaced? Is the correct machining-code loaded? Are the vitals of the machine in good running order (coolant, air pressure etc)? If a checklist is used for inspection, it should be used as a learning tool. Defects detected at final inspection must be corrected such that those defects never make their way to final inspection again.
- End-state check: Each task on the checklist must be designed to check for the successful end-state of that task. Wherever possible, successful completion should be confirmed by recording a measurement against a specification. Recording data achieves two goals: first, we know whether we are in-spec or out-of-spec, and second, this data will prove invaluable for future process improvement.
- Task-size: Breakdown the tasks on the checklist into the smallest possible executable element, ensuring a quick return to the checklist for the user. If tasks are too long, and return to the checklist is infrequent, a user may be tempted to proceed off of memory instead of following the checklist.
- Required communications: From my experience, quality and safety problems often occur due to a lack of structured communication between team members. Design your checklist to include structured safety communication. Manufacturing activities can often be rushed, chaotic, and stressful. Force a periodic time-out to review safety related task.
- Test: The check-list should be created by factory floor employees along with the key engineers and managers. It’s critical for successful implementation that managers, engineers, and technicians all use the checklists as a group before it is released to production.
- Usage: Always pre-assign tasks by role, or better yet, by name. Ensure everyone knows who owns each task by having each employee read out their name and assignments. If tasks are not pre-assigned, they are more likely to be skipped or pencil-whipped.
- Maintenance: It goes almost without saying that a checklist itself needs to be accurate and complete. Unfortunately, we have seen too many cases of out-dated checklists being pencil-whipped in order to ship a product on time. In most manufacturing environments, it will make sense to link checklists to the Bill of Material and Product Data to keep it accurate.
Trusting the Checklist
The final step to successful implementation involves breaking the users reliance on memory. Parts and features are constantly changing, and relying on memory often introduces an error in the manufacturing process.
As a manufacturing manager, your challenge therefore is to create a level of trust in the checklist so that your employees turn to their checklists to help them with speed and accuracy rather than choosing to rely on memory!
[PS: You can read more about the actual study, on which Dr. Gawande’s book is based and the results, here: New England Journal of Medicine].