“The Hawthorne effect refers to a tendency in some individuals to alter their behavior in response to their awareness of being observed. This phenomenon implies that when people become aware that they are subjects in an experiment, the attention they receive from the experimenters may cause them to change their conduct.”1

Last year, our sterile processing department completed a process improvement project that focused on how trays are sorted prior to decontamination. During the final presentation, I was asked a question that was as insightful as it was unexpected: “Did you truly solve the problem, or are we experiencing the Hawthorne effect?”

Handle on the concept 

As a new manager who had no idea what the Hawthorne effect is, but who also didn’t want to seem ignorant, I responded that I would circle back to them on it. Dozens of articles later, I had a handle on the concept, but not on how to answer the question.

The concern was valid; the project was initiated due to a seemingly endless loss of instruments and the time waste associated with disentangled, randomly combined trays. We identified a common issue that affected both the sterile processing and operating room teams, collected baseline metrics, in-serviced the stakeholders, and developed interventions that we felt would help improve the situation.

Over the course of three months, we collected weekly data and saw the deviations reduce significantly. Knowing that data doesn’t tell the complete story, we also collected feedback from the sterile processing and operating room staff and found that they were seeing the same progress that the data indicated.

In victory lap fashion, we summarized our results, colorful chart included, and confidently declared that we had solved a problem that had plagued the organization for years. The confidence wavered slightly when asked about the Hawthorne effect and crumbled entirely when, only months later in a separate meeting, we were again discussing how to address instruments sorted into the wrong containers.

The interventions were still in place and the staff composition was relatively the same. Lo and behold, we had our answer. We had not truly solved the problem, but had experienced the Hawthorne effect.

What is the Hawthorne effect?

From 1924–1932, a series of experiments was conducted at the Western Electric’s Hawthorne manufacturing plant in Cicero, Illinois. The goal was to evaluate how environmental factors affected the productivity of the team. Over the course of the experiments, researchers changed how bright the lights were, how the work groups were set up, and how closely the team was monitored. The measures yielded a surprising result when, in almost every situation, productivity improved.

Insights garnered from these experiments, later termed the “Hawthorne effect,” inform why a process improvement project may not achieve a long-term outcome. Whether on a factory floor or in your central sterile department, understanding the Hawthorne effect can help shape your data collection methods, prepare you for future project enhancements, and guide the trajectory of staff development.

An important caveat about the Hawthorne studies: Reviews of the data collected during the studies cast some doubt on the validity of the results and the methodology used. While any information collected nearly 100 years ago may not meet the rigors of our current scientific lens, the Hawthorne effect has a significant enough perception and impact on the workplace to be worthwhile to study and understand.

Key learnings for sterile processing from the Hawthorne studies

In situations where it is possible, data should be collected without the knowledge of the group contributing to the data. This should never be done in a way that is secretive or deceptive, as that will also skew your data and cause a host of issues in your department.

Rather, the data should be gathered as organically as possible. This takes additional effort on the part of the observer, but the results will be better. This is also an opportunity to implement a culture of quality checks within your department. If it is customary to audit trays on a daily or weekly basis, you can select data to look for without disrupting your workflow or introducing a new observer.

In our initial project, if we had been doing quality checks of trays in the decontamination area each day, we would have been able to pick some sets and check them for sorting accuracy. Neither the OR nor the SPD would modify their behavior because they both would have known that we already do quality spot checks.

Some problems can be corrected simply by observing them

With limited resources and an ever-increasing workload, it is important for healthcare professionals to distinguish between temporary problems and long-term obstacles. While the Hawthorne effect can derail your data, there is a way to make it work in your favor. 

An example of this in action is the problem of returning instruments to their storage location. Most sterile processing departments struggle from time to time with technicians not returning extra instruments at the end of their shift. If leaders begin to round regularly and check on this issue, the effect will be for the technicians to modify their behavior. No data needs to be collected and no project document needs to be written. Understanding the Hawthorne effect means that you can use the act of observation to drive better outcomes. 

Observation has a point of diminishing return

In the switch room study phase of the Hawthorne experiments, the output of production was closely monitored and compared to other team members. Some employees slowed down their productivity to avoid the impression that they were outshining their coworkers. The high-scrutiny environment caused employees to become disengaged and less productive. 

If your department has implemented a productivity metric that compares the number of trays assembled between technicians, you may discover the same result as the factory researchers: staff may slow down, start to hide errors, or stop communicating with leaders as suspicions grow. Lost trust can have a long-term impact when too much supervision gives the impression of micromanagement. 

It’s great to know what to do; it’s even better to know what to do differently

In more recent process improvement measures, our decisions have been guided by the awareness that our results can be greatly impacted by the underlying current of the team’s attitude and behavior. With hindsight being 20/20, it’s important to know what we could have done differently with our sorting accuracy project. 

  1. Establish routine processes that would allow us to collect data without introducing a new observer. Even if all elements are error-free during data collection, it is important to understand that the Hawthorne effect might impact your data. The team collecting information should establish a reasonable margin of error and track enough data to validate results. 
  1. Be patient. If something has been a problem for five years, it may be unreasonable to think that it will be resolved in a short time span. Improvement takes time, multiple iterations, and ongoing monitoring. There are likely problems you are saddled with now that a previous leader assumed they had solved. We shouldn’t sacrifice long-term solutions for short-term praise. 
  1. Be mindful of improvement fatigue. It is easy to move from one problem to another without taking a pulse on the impact it has on our team. The reason the production improved at Hawthorne was that the team was working faster, for more hours, and possibly with less accuracy. There will be times when rapid cycle process improvement is appropriate, but we can also contribute to burnout with constant changes, endless monitoring, and always asking the technicians to produce more. In the long run, it will be better to have fewer projects each year if they are well executed than have improvements of the month, week, or day. 

As we move from short-term gains to long-term change, we recognize the tremendous impact sterile processing professionals have on the healthcare system at large. There truly is no safe patient care without safe sterile processes. Understanding the impact of the Hawthorne effect ensures that the outcome is not just better for the next patient, but for patients for years to come. 


  1. Perera, A. (2021, May 28). “What is the Hawthorne Effect?” Simply Psychology. Accessed February 24, 2023. https://www.simplypsychology.org/hawthorne-effect.html