Stop the line

Lean methods emerged from manufacturing, where conventional wisdom was that the goal is to produce as many goods as possible, as quickly as possible. When Taiichi Ohno introduced the Andon cord at Toyota, authorizing every employee on the assembly line to immediately halt production when they noticed a problem or defect, even people in his own company thought he was crazy.

In fact, those managers who implemented the Andon procedure and stopped the line had a huge drop in productivity, and the managers who did not saw their numbers stay steady. But ultimately, Ohno’s system was proven to be effective. Managers who had stopped the line soon caught up to and then exceeded, their counterparts, producing more cars, more efficiently, and with more reliable quality.

As Ohno had anticipated, stopping the line changed the focus of the entire auto plant away from simply maximizing their current processes, toward improving them. The temporary loss in production was an investment in building better processes. Is your company prepared to do the same?

Risks of “Stopping the Line”

risks of stopping the line

Of course, in any company, stopping the line is beset with risks:

Lost revenue

The obvious risk of stopping the line is that, for some period of time, your company is not producing a product. When production is stopped, your company is spending money without earning any. While the degree of risk depends on how much a margin your company has, no business can afford to remain in that state for long.

Missed deadlines

Empowering front-line employees to halt production also carries the very real risk that you may miss deadlines promised to customers and partners. Again, depending on the company or the industry, this can pose an enormous risk to future business relationships, and may jeopardize some contracts.

Unstable supply

Even without deadlines, stopping production may mean that your product isn’t in consistent supply for your customers. This might not only disappoint customers, but it creates an opportunity for competitors. People who need your product right now (particularly if you’re using a “just in time” inventory system) will be tempted to look elsewhere.

For some businesses and industries, there may be still more risks. Perhaps your technology isn’t fast and easy to stop and restart, or your delivery windows are tight. If you have to catch a red-eye flight, make a FedEx drop-off, or have a product in the stores for Black Friday, a delay of even a few minutes can cost days or weeks of negative consequences.

Benefits of “Stopping the Line”

benefits of stopping the line

However, as Ohno proved with Toyota, there are definite advantages to enacting production stopping procedures:

Improved quality

Of course, the obvious benefit is that you identify quality issues and correct them before you ship the product. This results in better products and higher customer satisfaction. But stopping the line also has other benefits that may be less obvious.

Reduced time spent in quality control

Whatever the quality control mechanism may be for your product or service, delivering higher quality products, to begin with, speeds the process.

Process improvement

Mistakes and errors are identified and corrected earlier, so that fewer mistakes are made overall.

Increased employee engagement

When employees feel trusted and personally empowered to be attentive to product quality, they feel more responsible and more deeply engaged. Their sense of ownership and accountability improves, and it drives better engagement and performance.

Prevents accumulation of problems

Depending on the industry, it’s possible that small quality issues in one area or department cause another department delays and workarounds, which in turn affects another department, and another.

Over time, the entire system may end up accumulating a large number of idiosyncratic bugs, issues, problems, and workarounds that becomes difficult to uproot and solve. This is particularly an issue in software development, and a strong argument for stopping the line early.

“Stopping the Line” in Practice

stopping the line in practice

Lean systems have been applied widely in many companies and industries that are not directly in manufacturing. So, what does “stopping the line” actually mean?

Stopping the line means two things:

  • Temporarily halting production under the current conditions or with the current product
  • Immediately summoning help

Stopping the line means that everyone on every level is immediately focused on solving this problem, and individual people, teams, or departments don’t have to try to solve it alone.

When done correctly, stopping the line results in immediate, productive, support and collaboration.

If you implement “stop the line” policy, but don’t also convene a rapid, systemic, effective response, then you are creating more problems than you are solving, and you run the risk of punishing the employee who triggered the alert.

Stopping the line may be triggered by a front-line employee, or a quality tester, or even a customer, who has identified a crucial flaw in a product. It may be a team lead or department head who feels that their group cannot be effective under current conditions, for reasons beyond their range of responsibility. It may even be triggered by a technical failure. But once the andon is activated (actually or virtually), a few things happen:

Obeya is the all-hands-on-deck approach to problem-solving

Affected employees, departments, and leadership convene to identify the problem and determine consequences and ramifications.

Obeya puts problem solvers and decision makers in the same place at the same time, so that nobody has to wait for more information or for permission to proceed.

If the company has implemented Lean management globally, other departments and employees will offer assistance during the Obeya as appropriate.

Jidoka is the act of actually stopping production

It’s possible that, when the alert is triggered, a team or leader may decide that it’s not necessary to actually stop, so it’s not the inevitable result of the Andon trigger.

However, particularly in software and tech companies, Jidoka may be necessary, because problems and solutions in one area may require changes in another. If management decides that some departments keep working while others stop, they risk incompatible solutions.

Communication

Many places that use Kanban boards have a special swimlane or card for Jidoka. It is important that not just affected employees, but the entire organization knows what is happening, who is affected, and what the next steps are. Communication is constant and active until the problem is resolved, and then the resolution is communicated to all.

Solution implementation and continuous improvement

In the Obeya, everyone is focused on solving the current, urgent problem. But it is important that, after the situation is resolved, reflection and learning follow it, to see if there are lessons that apply to other situations, or how the process can be improved to prevent future occurrences of similar problems.

Stopping the line is an important concept in Lean systems, safeguarding product quality, investing in improved processes, and empowering employees. The degree to which a given company can implement this practice depends on their industry and business needs.

But remember that stopping the line early in production contains negative downstream consequences and adds value for the customer. It’s a fantastic tool when used wisely, and a crucial part of seeking perfection.

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