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The Psychology Behind Sterility

Sterile reprocessing
Sterile reprocessing

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How Psychological Phenomena Affect the SPD

Sterile processing departments (SPDs) play a crucial role in healthcare facilities, ensuring that medical instruments and equipment are properly sterilized and safe for patient use. The effectiveness and efficiency of SPDs depends not only on technical skills and protocols, but also on the behavior and interactions of the personnel within these departments. This article explores the influence of three psychological phenomena—the Dunning-Kruger effect, the halo effect, and the bystander effect—on the performance and dynamics of SPDs.

The Dunning-Kruger effect

The Dunning-Kruger effect is a cognitive bias in which individuals with low ability at a particular task tend to overestimate their proficiency.¹ This can have profound implications in an SPD. Sterile processing departments require personnel to adhere to strict sterilization protocols, operate complex equipment, and maintain a deep understanding of microbiology and infection control. However, employees who suffer from the Dunning-Kruger effect may incorrectly believe they possess a high level of competence when, in reality, their skills are insufficient. Essentially, this is the technician who stands on third base and assumes they hit a triple.

This overconfidence can lead to a multitude of problems within an SPD. Inaccurate sterilization procedures may result in contaminated instruments, posing a significant risk to patient safety. Such personnel might be resistant to training or fail to identify their need for improvement, hindering professional growth and the department’s overall efficiency.

During a training meeting, our director asked if any of us had released an unsterile load of instruments. There were a few hands that went up, but most of the room was quiet. We worked in a facility that required monitoring every load with a biological indicator, as well as a strong 200% verification for load documentation. Because of those controls, we were overly confident that there was no risk of releasing an unsterile load.

However, that isn’t quite how sterility assurance works. When we complete all cleaning, inspection, and sterilization steps correctly, there is a six-log reduction of the microbial load on soiled instruments. This translates to a one in one million chance that a pathogen survives. While this is an industry-leading level of quality, we cannot be 100% confident that we have never released an unsterile load. One risk of the Dunning-Kruger effect is the assumption that any errors made in the reprocessing cycle can be overcome once the instrument set is in the autoclave. Each deviation from the instructions for use (IFU) reduces the overall sterility assurance.

To address the Dunning-Kruger effect, management should emphasize ongoing training, performance evaluations, and feedback. Encouraging a culture of humility and continuous learning can help mitigate the overconfidence seen in some personnel, ultimately leading to a safer and more efficient work environment.

The halo effect

The halo effect is another cognitive bias where a single positive trait or action of an individual influences overall judgments.² In an SPD, the halo effect can affect how personnel are evaluated and promoted. If a team member consistently excels in one aspect of their job, such as instrument assembly, they may be perceived as competent in all aspects, even if they have weaknesses in sterilization or recordkeeping.

This can lead to uneven performance evaluations and promotion decisions. The impact of the halo effect can be especially problematic when it comes to promoting individuals into supervisory or leadership roles. Just because someone excels in one area doesn’t necessarily mean they possess the skills required to manage a team or department effectively.

While the ability to train other staff is an important part of our repertoire as sterile processing professionals, not all technicians thrive with direct reports. Many of us have worked with an experienced technician who could grind through trays in decontam quickly, and with no mistakes, but who may not have been the best trainer. To promote and retain these talented experts, SPDs can develop advancement opportunities that do not fall into the standard categories of lead, supervisor, manager, or director. Roles like instrument coordinator, process and data specialist, and quality manager are all positions where staff’s “halo” talents can shine, without being pushed into a no-win situation.

The inverse of the halo effect can also have an impact. Some individuals are talented and natural leaders, but may not be your highest producing technicians. We see an analog of this in the world of sports. Being a great player does not mean you will be a spectacular coach, and being a less-than-stellar player wouldn’t disqualify you from leading a team.

To mitigate the halo effect, SPDs should implement comprehensive and objective performance evaluations. These evaluations should consider a range of skills and responsibilities, not just a single area of excellence. Additionally, leadership positions should be based on a demonstrated ability to lead, mentor, and make decisions, rather than just on technical competence in one aspect of the job.

The bystander effect

The bystander effect is a psychological phenomenon where individuals are less likely to help or take action in an emergency or problematic situation when others are present.³ In an SPD, where personnel work as a team to ensure instruments are sterile and ready for patient use, the bystander effect can hinder problem resolution and efficient workflow.

For example, if an employee notices a potential issue during the cleaning process, such as a broken instrument, but assumes that someone will catch it during assembly, the problem may go on, leading to noncompliance with safety standards and potentially compromising patient health. This diffusion of responsibility can be particularly dangerous in a healthcare setting.

Recently, a whistleblower from St. Luke’s Hospital in Kansas City, Missouri, alleged dangerous practices that included rusted equipment, customized instruments without valid IFUs, and a lack of environmental controls.4 How many of these defects were observed by sterile processing staff, operating room staff, and even surgeons before being passed on to worry about by the next person?

To counteract the bystander effect, SPDs should emphasize a culture of accountability and clear communication. Employees should feel empowered and encouraged to speak up when they observe issues, and the department should have established protocols for addressing and resolving problems promptly. Every SPD should see themselves as patient safety advocates. Creating an environment where everyone understands their role in maintaining safety standards can reduce the negative impact of the bystander effect.

The Dunning-Kruger effect, the halo effect, and the bystander effect are three psychological phenomena that can significantly impact the performance and dynamics of an SPD. Awareness of these biases is crucial for creating a safer and more efficient work environment in healthcare facilities. By addressing these psychological phenomena through training, performance evaluations, and a culture of accountability, SPDs can better ensure the safety of patients and the effectiveness of their operations.


  1. The Decision Lab, “Why can we not perceive our own abilities? The Dunning-Kruger Effect explained,” n.d., Accessed November 10, 2023,
  2. Neugaard, Britta, “halo effect,” Encyclopædia Britannica, Inc., October 6, 2023,
  3. Stavert, Robert R., M.D., M.B.A., and Lott, Jason P., M.D., M.S.H.P., The New England Journal of Medicine, “The Bystander Effect in Medical Care,” January, 3, 2013,
  4. McMaster, J., “Saint Luke’s operates on patients with ‘rusty’ and ‘damaged’ equipment, according to complaint,” October 17, 2023, KSHB 41 Kansas City,

Author: Garrett Hollembeak, Featured, Sterile Processing

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