Conventional wisdom consists of ideas that are so widely held that they are believed to be true without much critical analysis. The problem is that conventional wisdom isn’t always true.

In fact, it can actually be an obstruction in the path to truth because clinging to long held beliefs is easier than adjusting to new information.

Lean organizations must work to challenge conventional wisdom if they want to end the habit of doing things a certain way purely because that’s the way it’s always been done.

Here are some long held truisms that Lean teams can forget about.

“Bigger is Better”

The Lean management approach and several other business process methodologies like Six Sigma and TQM can be traced back to Toyota’s efforts to improve its operations after WWII. One of the first things that they discovered is that bigger isn’t always better.

They found that they could be far more efficient with smaller inventories and by processing smaller batches at a time. The “pull” method enabled by Kanban boards and other visual signals allowed them to have exactly the right number of parts in the right place at the right time.

This lesson can be applied to any number of industries. “Bigger” is usually equated to waste, not value.

“The Executive Team Knows What’s Best”

People rise to the executive level in organizations because they are smart, experienced and effective.  Therefore, they should be the ones to institute changes and make decisions. Or so the conventional wisdom says.

Lean organizations find that this is not true at all. Opportunities for improvement can (and should!) be identified by people at every level of the organization, and some of the most innovative ideas come from employees on the front line.

“Standardization Kills Creativity”

This is one of the most harmful, and deeply held beliefs that we run into in our improvement work with organizations.

Leaders are afraid to implement Standard Work because they believe it is the equivalent of treating employees like robots or that it robs people of the incentive to improve. This couldn’t be further from the truth.

What standardization does is create a baseline so that employees know exactly what they are improving upon. It also makes it possible to measure the impact of each new process innovation.

“Good News Travels Fast”

When an opportunity for improvement is successfully implemented or a team achieves a breakthrough, too many leaders simply assume that everyone will find out about it. Of course, that’s not the case at all.

Perhaps those closest to the work will know about improvements, but it is important that positive results are shared far and wide. Improvement broadcasting builds enthusiasm for Lean work and allows all parts of the organization to capitalize on every success.

“Too Many Cooks Spoil the Broth”

Some departments are so walled off that they should just have a “Stay out of my kitchen,” sign taped to the door. This is unfortunate because often the best ideas come from cross-functional teams working together and sharing new points of view.

When it comes to improvement, a different bit of conventional wisdom makes more sense … the more the merrier.

“If It Ain’t Broke, Don’t Fix It”

Boo. This is the worst of all. Lean organizations reject this flawed thinking out of hand. There’s a big difference between "not broken" and "perfect." There’s no need to wait for a major crisis or complete meltdown to examine how waste can be eliminated and value increased. Improvement is always possible.

Critical thinking is an important part of the Lean method. Assumptions should be challenged at every opportunity, starting with the one that conventional wisdom is always wise.