While asking what is the number one contributing factor to human errors seems like a simple question, the reality is far more intricate. Expert consensus across fields like healthcare and aviation indicates that mistakes are the result of a chain of events, not a single deficiency. In fact, focusing solely on individual blame can prevent organizations from fixing the underlying systemic flaws that allow errors to happen in the first place.
The fallacy of a single cause
For decades, industries have operated under the assumption that human error is a product of individual shortcomings, such as a momentary lapse in judgment or attention. While such errors, known as "active failures," are the immediate cause of an incident, they are often the last link in a long chain. James Reason's "Swiss Cheese Model" illustrates this perfectly. Each slice of cheese represents a defensive layer within a system, with holes representing a weak point. An error occurs when all the holes align, allowing a hazard to pass through the system's defenses. These holes are created by latent conditions—underlying issues within the organization or environment.
Deconstructing cognitive limitations
At the individual level, our brains have inherent limitations that make us prone to error, especially under pressure. These cognitive limitations manifest in several ways:
- Cognitive Overload: When we are faced with too much information or too many tasks at once, our brains can reach their processing limit. This can lead to slower problem-solving, difficulty retaining new information, and an increased likelihood of error.
- Attentional Failures: Slips and lapses are errors of attention or memory. A slip is performing an action differently than intended (e.g., dialing the wrong number), while a lapse is forgetting to perform an action altogether (e.g., forgetting a step in a procedure). Distractions, such as a noisy environment or a ringing phone, significantly increase these failures.
- Decision-Making Flaws: Under stress, the brain may switch from an analytical, thoughtful mode to a more reactive, heuristic-based approach. While heuristics (mental shortcuts) are often efficient, they can lead to cognitive biases and flawed judgments, particularly in complex or novel situations.
The physiological tax of fatigue and stress
Among the most cited human factors, fatigue and stress emerge as highly influential, especially in high-stakes environments like healthcare.
- Fatigue Impairment: Studies have shown that being awake for 17-19 hours can impair performance to a degree comparable to a blood-alcohol level of 0.05%. Fatigue impairs attention, vigilance, memory, and decision-making. For healthcare workers, long shifts and chronic burnout are major risk factors for mistakes.
- Burnout: Beyond simple fatigue, burnout is a state of physical and emotional exhaustion that can severely compromise a person's cognitive function. Research from Stanford found that medical errors tripled in units where physicians reported high levels of burnout, suggesting burnout is a bigger driver of mistakes than a poor safety environment alone.
- Stress: High levels of psychological stress can trigger a fight-or-flight response that negatively impacts focus and logical reasoning. In an emergency, for example, stress can cause a practitioner to make hasty decisions or miss crucial details.
The systemic roots of error
Organizations play a powerful role in enabling or preventing human errors. Systemic failures often lie dormant until an active failure triggers a negative event.
- Poor Communication: Communication breakdowns are a top cause of medical errors and workplace accidents. Misunderstood instructions, failure to communicate critical information during patient handoffs, and hierarchical communication structures can all lead to catastrophic consequences. Tools like standardized "read-back" procedures are designed to mitigate this risk.
- Inadequate Training and Resources: Insufficient education, a lack of continuous development, and high workload are consistently identified as contributing factors to error. If staff are not adequately trained on complex equipment or processes, or if they lack the resources to perform their job correctly, mistakes are inevitable. A shortage of nurses, for example, can increase workloads and heighten the risk of adverse events.
- Flawed Design and Technology: Poorly designed processes, confusing interfaces on electronic health records, and even look-alike drug packaging can contribute to mistakes. While technology can improve safety, it can also introduce new failure points if not implemented carefully.
Common factors influencing error
| Factor | Characteristics | Impact on Error | Example | Description |
|---|---|---|---|---|
| Fatigue | Sleep deprivation, long hours | Reduces attention, vigilance, and judgment | A surgeon performing a complex procedure after a long, stressful shift. | Impairs cognitive function, leading to lapses and mistakes. |
| Cognitive Overload | Too many tasks, complex information | Hinders processing of new information | An ER nurse fielding multiple critical alerts and patient needs simultaneously. | Increases mental effort and slows down decision-making. |
| Poor Communication | Lack of clarity, misinterpretation | Leads to misunderstandings and missed steps | A technician misinterpreting a verbal order for medication dosage. | Breaks down vital information transfer, creating errors. |
| Complacency | Overconfidence, reduced risk awareness | Causes lowered vigilance and oversight | An experienced pilot relying too heavily on automated systems. | Leads to missed cues and failure to detect emerging problems. |
| Systemic Pressure | Time constraints, understaffing | Creates a rushed environment, increasing risks | A hospital discharging a patient prematurely to free up a bed. | Prioritizes metrics over safety, making errors more likely. |
Creating a culture of safety
For organizations, the most powerful way to mitigate human error is to move away from a culture of blame and toward a culture of safety. This involves implementing strategies that address the systemic and environmental factors that contribute to mistakes. A robust safety culture encourages open communication and confidential reporting of near-misses and errors without fear of reprisal. This approach helps identify weak points in the system, allowing for corrective interventions and process improvements.
Strategies can include:
- Leading by example: Leaders must demonstrate their commitment to safety by consistently following protocols and showing that safety is a top priority.
- Empowering employees: Give employees the authority to halt an unsafe procedure and provide channels for reporting concerns anonymously.
- Continuous improvement: Regularly review incident data and conduct risk assessments to identify trends and proactively address hazards.
- Training and education: Provide ongoing, interactive training on safety protocols and human factors, ensuring the information is engaging and retained by employees.
- Reinforcing safe behavior: Recognize and reward employees who exhibit safe practices and proactively address potential risks.
While we may never eliminate human error entirely, we can build more resilient systems that account for human limitations rather than simply punishing them. The number one contributing factor is not a single issue, but the collective failure to build systems that protect against the inevitable reality of human fallibility. For more information on creating effective patient safety systems, consult resources from the National Institutes of Health.
Conclusion: Beyond a single culprit
Rather than asking what is the number one contributing factor to human errors, a more productive approach is to understand the constellation of factors involved. This includes individual cognitive and physiological states like fatigue and cognitive overload, as well as broader systemic issues such as poor communication and inadequate resource allocation. By shifting focus from individual blame to systemic improvement, organizations can build stronger defenses and create environments where mistakes are less likely to occur. A comprehensive strategy that addresses these interconnected issues is the most effective path toward reducing human error and improving overall health and safety.
