The Swiss Cheese Model of Safety

Dairy Farmers of Wisconsin

"Two is one, and one is none."

—A military adage

U.S. President Donald J. Trump was on his way to Davos, Switzerland, on January 21, 2026, to speak at the World Economic Forum when a "minor electrical issue" forced Air Force One to return to Joint Base Andrews in Maryland. The lights in the press cabin went out briefly. 

A decision to return to Joint Base Andrews was made "out of an abundance of caution," said presidential press secretary Karoline Leavitt. 

The president and his party, including Secretary of State Marco Rubio, and the traveling press corps, were transferred to two different planes for the 7.5-hour flight to Zurich. 

The former head of the National Transportation Safety Board, Mary Schiavo, said, "This has to be one of the best-maintained planes in the world. But there are things on every aircraft where when the warning light comes on, you have to turn around and go back to address it."

Don't ignore the warning lights is good advice. 

Swiss cheese explained

The lush valley in western Switzerland known as Emmental, about an hour and a half or 121km from Zurich, is the birthplace of Swiss cheese, according to Wisconsincheese.com. The website describes this as an "alpine-style" cheese made in high-altitude pastures. 

When Swiss immigrants arrived in Green County, Wisconsin, in the late 1800s, they brought cheesemaking techniques with them. And we're all glad they did.

Why does Swiss cheese have holes?

Historians at the association say it's due to the cheesemaking process, which slowly releases carbon dioxide, forming small pockets of air called "eyes" during aging. 

Holes and slices

The Theory of Active and Latent Failures was proposed by James Reason, Ph.D., a psychology professor from the University of Manchester, in his book, Human Errors. Dr. Reason's initial interest was in complex systems, such as healthcare. His thesis was that accidents are caused by a breakdown or absence of safety barriers within the system. 

The Swiss Cheese Model is a popular representation of Dr. Reason's work, in which absent or failed barriers at each level are represented as holes in the cheese. 

Post-accidents are evaluated by identifying which slice of the Swiss cheese broke down and mitigating their recurrence.

The U.S. government admitted in a court filing last year that it was partially at fault in a midair collision between American Eagle flight 5342 and a U.S. Army Black Hawk helicopter that killed 67 people on January 29, 2025. The CRJ-700 passenger jet, owned by PSA Airlines, was attempting to land on runway 33 at Washington's Ronald Reagan National Airport. 

The role of redundancy

In the Swiss cheese model, the holes represent weaknesses in individual parts of the system, and they continually vary in size and position across the slices. The system produces failures when holes in each slice momentarily align, permitting, in Dr. Reason's words, "a trajectory of accident opportunity." 

Therefore, there is a necessity for redundancies. 

"Redundancy in aviation refers to the duplication of critical components or systems to enhance reliability, usually through a backup or failsafe. This ensures that if one part of the system fails, others can take over its function without compromising safety," say the experts at Melbourne Flight Safety. 

"The key areas are avionics, power, and flight control systems," they note.

Even with redundancy in the cockpit on general aviation and flight decks for larger aircraft, pilot error accounts for 60% to 80% of all incidents, according to the NTSB and Federal Aviation Administration. Mechanical failure and weather conditions are also important factors. 

Commercial air travel remains the statistically safest mode of transportation, with fatality rates near zero per 100 million passenger miles, says the University of Nevada, Las Vegas.

What other types of systems require backups?

Power grids, water supply systems, communication networks (such as data centers), and transportation infrastructure (such as additional highways, bridges, and tunnels). 

As someone said, "We're all connected, and we're all vulnerable."

One other category to consider is succession plans, which are a form of strategic redundancy. "They are designed to ensure business continuity and reduce dependence on any single individual. Normally, redundancy implies elimination, but in this case, it means backup," suggests CPA firm, Moss Adams. 

Murphy's Law

Sean Gold, the founder of TruePrepper in North Carolina, says that "The 'two is one and one is none' idea means that you should expect one thing to go wrong with equipment, survival gear, plans, and even people."

"Even the most careful plans and robust equipment need backups," Gold emphasizes. 

KCRA TV in Sacramento, California, reported that three survivors of the deadly avalanche near Castle Creek used their safety gear to rescue fellow skiers buried in snow. Six members of the group survived while nine died. It was the deadliest avalanche in modern California history. 

There's a relationship here with an epigram known as Murphy's Law, "Anything that can go wrong, will go wrong." Yet sometimes the biggest risk is doing nothing.  

Nevertheless, the goal of preventing accidents and not repeating bad decisions is achieved by taking the time to learn from past mistakes and institutionalizing those findings.

A visible example of that principle is the Space Shuttle Challenger explosion forty years ago, which occurred on January 28, 1986, and took the lives of seven crew members just 73 seconds into the launch, including schoolteacher Christa McAuliffe. 

The lessons there — don't yield to internal management pressure and don't launch in cold temperatures — may partly explain why NASA rolled back the Artemis II moon rocket to its hangar last month so engineers could look for possible helium leaks. 

Learning from the past and leveraging timely knowledge are ways to prevent cultural, systemic, and mechanical holes from aligning. Think about that the next time you're enjoying a slice of Swiss cheese. 

Strategist.com

© Bredholt & Co. 

Overcoming Barriers to Mission

What stands in the way of accomplishing the mission of your organization?

Is it the competition?  The right people?  Not enough working capital?  Maybe it's a problem with focus, commitment, or trust.  Is there uncertainty as to what the mission is?  

Perhaps it has to do with some or all of the above.  

After thinking about this I decided to make a list of reasons why some fall short in fulfilling their mission and how these barriers might be overcome. 

The underlined concepts below are drawn from the book, Organizational Culture, and Leadership, by Dr. Edgar Schein, with our commentary. Dr. Schein, an MIT professor emeritus and a guest writer on this site, is regarded by some as having written one of the more influential volumes on management. 

From our book notes, here are seven possible barriers with countermeasures for each:

Barrier No. 1

There is consensus on the core mission but the group does not share common goals.   

In fact, those who make up what is now called a "team" can have widely divergent views when it comes to setting goals.  The absence of commonality comes from different backgrounds, experiences, and world views. 

Nothing new here. 

The challenge for top management is melding these unique personalities and perspectives together to achieve a common purpose. Sharing deeply things of value is a distinct competitive advantage.

Barrier No. 2

The mission is often understood but not well articulated. 

One of the duties of a leader is to explain things.  Telling is easier but explaining requires a deeper understanding of the situation.  Repeating a statement of mission does not necessarily mean that employees and others know what's inside since no message guarantees its own meaning.

The main ideas that cause a business to exist have to be periodically clarified and updated.  Why?  Circumstances change.  The original and current contexts of the business are likely very different.   

 

Employees tend to respond favorably when leaders and managers illustrate the mission in tangible ways.   Nothing wrong with communicating values but knowing the desired outcomes is a benefit to all. 

Behavior may be the clearest articulation of mission.   

Barrier No. 3

The group does not have a common language and shared assumptions on the goals making it difficult to move from the abstract to the concrete realization of something.

Imagine the next time you're on a flight that the pilot and control tower are trying to communicate with each other at the same time using different languages and radio frequencies.  A scary thought. 

So it is with those in a business or nonprofit simultaneously communicating mixed messages on multiple channels.  Another scary thought. 

Communication, including feedback, is everything when it comes to accomplishing something worthwhile. 

A carefully constructed list of internal and external assumptions can be worth their weight in gold.  They are the basis of common understandings and should find their way into conversations and plans.

Barrier No. 4

Not understanding that mission and strategy can be rather timeless while goals must be formulated for what to do next year, next month, and tomorrow.

Part of the problem may be an omission of goals altogether.  There's talk about vision, mission, and strategy, but goals are nowhere to be found.

When properly set, the right goals complete the strategic puzzle.  They provide high resolution to the mission and facilitate implementation, including accountability.  Goals also make it possible to measure progress. 

Yet the real benefit in goal-setting, according to Dr. Schein, "is that the process often reveals unsolved issues or lack of consensus around deeper issues."

Barrier No. 5

Mixing strategy and goals since strategy concerns the evolution of the basic mission--while operational goals reflect short-run tactical survival issues.

Knowing the difference between strategy (set of options and use of available resources) and goals (desired results usually with a timeline) is essential for effective management decisions. 

Taking time to know the proper relationship between strategy and different kinds of goals could be the difference between profit and loss--and the future of the business. 

Barrier No. 6

Lack of clarity on the means by which goals will be met.

Goals need to be set and owned by those responsible for their achievement. They are also the ones to identify the best means of meeting a particular goal.  

If a major goal is to be met someone has to take the lead in communicating the goal, how it was established, and why it's being put in place.  Reaching this goal means what to the organization?

A clear goal, with credible leadership, improves the chances of departments pulling together to profitably make soap or software.  

Meeting goals is a matter of personal responsibility, even in a team environment.

Barrier No. 7

Failing to agree on what indicators to pay primary attention to in order to decide how well the organization is doing and what corrective action, if any, needs to be taken.

Ever notice when staying in a hotel how the Kleenex tissue goes from white to beige with high usage?  The color change is an indicator that the tissue supply is getting low.  Housekeepers are trained to look for this and (hopefully) take steps to keep the box filled.

Does your company have in place agreed upon, and visible, indicators to measure progress and alert everyone to a potentially serious problem?   Only a select list of indicators is of any practical use to management and staff. 

The right indicators won't be full-proof.  But they can go a long way in maintaining health, avoiding or minimizing trouble, and determining a possible course of action if something arises. 

Indicators are worthless if ignored. 

That's a key finding from the investigation into the tragic launch of Space Shuttle Challenger on 28 January 1986 which killed all seven crew members.  The vehicle exploded 73 seconds into the flight.  

Warnings about a flaw in the O-ring seals from as far back as 1977, the primary cause of Challenger's structural failure, were ignored by some NASA managers, according to the Warren Commission report.  The dangers of launching in cold temperatures (31 F/-1C) that fateful morning was also disregarded.

Final thought

No matter the size, history, or success of an organization, there will be obstacles along the way.  However, if the mission is that important, then finding the means to overcome one or all seven barriers listed above, should be a priority on your leadership agenda.  

Strategist.com

(C) Bredholt & Co.