"Avoid a 30% drop in productivity with these 5 tips!"

How One Bad Apple Makes Your Team 30% Less Productive

Did you know that having a toxic colleague within eight meters of you reduces your output by 30%? And if a top performer is nearby, your performance rises by 15%.

This comes from research by the Kellogg School and Cornerstone on Demand. The technical term is spillover.

Negative spillover costs U.S. companies $12,800 per toxic employee. And the real costs are far higher: psychological insecurity, moral decay, bullying, absenteeism, and burnout.

With the growing importance of hybrid work and frequent career switches, this deserves every leader’s attention.

Why negativity counts twice as much

Interestingly, negative spillover is almost twice as strong: 30% loss versus 15% gain.

Researchers also found something else: negative behavior spreads instantly. The good news? The effect disappears just as quickly once the bad apple is gone.

Positive influence builds more slowly, usually over a month. Positive spillover works best when employees complement one another. A fast colleague lifts up a slower one, without slowing down themselves. Skills reinforce each other, and the entire team grows.

What science tells us

Later peer-reviewed studies confirm this phenomenon:

• Murphy (2019) studied U.S. Army recruits. Soldiers who worked with colleagues who had a criminal record were more likely to misbehave themselves. The effect was strongest among young recruits and often mirrored the behavior of the “bad” peer. Negativity spreads like a virus.

• Kamei & Ashworth (2023) randomly paired employees into duos. Teams with bigger skill gaps performed better. The least skilled worker improved significantly, and that gain spilled over into other tasks.

  
  

The conclusion is clear: who sits near you subconsciously shapes your behavior.

From joke to sabotage

Organizational anthropologist Jitske Kramer shows how harmful behavior escalates: from jokes and excuses to gossip, poor communication, and eventually open resistance or resignation.

You may recognize this: one sarcastic joke during a meeting and suddenly tension fills the room. If not addressed early, it grows into sabotage. By the time someone mentally checks out, it’s often too late for a leader to win them back.

How to harness positive spillover

Luckily, it also works the other way. When skills complement one another, synergy emerges. The fast colleague lifts the slower one. The slower, more analytical colleague keeps an eye on details. The structured teammate helps the creative one turn ideas into reality. The creative sparks out-of-the-box thinking in the structured. Mutual reinforcement leads to collective growth.

As a leader, you hold a powerful lever. Not through more meetings, reports, or expensive training, but by carefully deciding who sits next to whom.

What leaders can do

• Place high performers next to colleagues with growth potential. Give it at least a month to see results.

• Address sabotage behavior immediately. Stop jokes and gossip before they escalate, and lead by example.

• Prevent clusters of negativity. Isolate persistently negative employees in time. One bad apple can infect three good colleagues.

• Be willing to let go of toxic employees. Their impact outweighs any output they deliver.

• Experiment with workspace and team layouts. Sometimes a small change boosts performance.

  
  

Time to take a hard look in the mirror

Who is within eight meters of you? Are they lifting your team up or dragging it down? Do you recognize sabotage behavior: in others, or maybe even in yourself?

As a leader, you are the role model. How you handle negativity sets the norm. Choose consciously: create an environment where positive spillover can thrive, and toxic behavior never gets the chance to take root.

Action!

Want to discover how subconscious influence techniques can help you build more resilient, productive, and engaged teams? Book an introduction call and learn how small interventions can have a big impact.