Two decades after the patient safety movement began, there is still a troubling disconnect regarding one of its key tenets: a needed transformation of the nurse work environment to protect patients from medical errors and other adverse events.

The modern patient safety movement essentially began in 1999 with the Institute of Medicine’s (IOM’s) To Err Is Human report, which revealed that medical error was one of the leading causes of death in the United States.1 The IOM — now known as the National Academy of Medicine — issued a companion report in 2004 that underscored that the nursing work culture is a critical factor in patient safety.2

These reports showed that, with regard to patient safety, nursing work culture “is the number-one most important thing. Patients will never be safe as long as work environments are as chaotic as they are, with such high levels of nurse burnout and stress,” says Linda Aiken, PhD, RN, FAAN, FRCN, a nursing professor and director of the Center for Health Outcomes and Policy Research at the University of Pennsylvania in Philadelphia.

Aiken, author of several critical occupational nursing studies, including some of the research that led to passage of California’s landmark nurse staffing law, says the nurse work culture is not just a key factor for patient safety — it is the key factor.

“If you have a poor overall work environment, you could not possibly have a good culture of patient safety,” she says.

In her most recent study, Aiken and colleagues researched 535 hospitals in four states in 2005 and 2016. “Survey data from thousands of nurses and patients showed that patient safety remains a serious concern,” the researchers found. “Only 21% of study hospitals showed sizable improvements (of more than 10%) in work environment scores, while 7% had worse scores.”

It should be noted that To Err Is Human was released with considerable fanfare and the immediate endorsement of then-President Bill Clinton and the Department of Health and Human Services. The nurse work environment report was released in comparative obscurity five years later, and that may be a factor in Aiken’s findings.

“In spite of the IOM recommendations to improve nurses’ clinical work environments to keep patients safe, in 2015-16 a third of nurses in the study hospitals rated the work environment in their hospital as only fair or poor,” Aiken and colleagues found. The concept of “a blame-free safety culture where staff feel empowered to question authority has not been fully achieved,” they concluded.

The researchers also found considerable evidence of nurse burnout, “a known patient safety hazard,” with roughly one-third of RNs scoring high on a common measure of the condition.

‘Shockingly Poor’

Hospital Employee Health asked Aiken to comment further on her findings in the following interview, which has been edited for length and clarity.

HEH: While there has been some success, you make the point that the patient safety movement that began with the first IOM report in 1999 has left out the nursing work environment to some extent.

Aiken: We asked, 20 years later, has anything gotten better? We took a snapshot today of what proportion of hospitals have really improved their environments. And those that improved, have they really gotten better in terms of patient safety and in terms of good outcomes for nurses? The answer is, yes.

We concluded in our paper that one of the reasons why the progress in reducing patient harm for medical errors has been so slow and uneven is that the major recommendation of the IOM was to improve the nurse work environment. We found that only 20% of the hospitals really made substantial change. We used a pretty low bar, which was what percentage of hospitals have improved their work environment by at least 10%. It was only 20% of hospitals. Close to 80% either declined or stayed the same — which is amazing.

HEH: Many nurses in the study rated their hospital work environment as either fair or poor. What led to the breakdown in the idea that patient safety was linked to a better work culture?

Aiken: I think the major disconnect that came out of the IOM report was that the work environment was never identified as a patient safety intervention, even though it was a headliner. But if you look at patient safety, they never mention the work environment, so it kind of got lost.

All kinds of useful things have been done in controlled circumstances to reduce harm to patients, like checklists in response to central-line infections. But what we find in real practice is that if you try to superimpose those things on a poor work environment, where nurses really don’t have enough time to surveil patients or even to provide all the care that is required, none of those safety initiatives are really implemented at the level of reliability that results in reductions to patient harm. That was the original idea behind the IOM report — they said there is something not right in the environment in which healthcare is delivered.

HEH: You note that this remains a problem even after a series of measures on a safe work environment were subsequently developed by groups like the Agency for Healthcare Research and Quality.

Aiken: You see in our paper that the patient safety environment is shockingly poor still today. You have 50% of nurses that say that their mistakes are held against them. That is a key flaw in this culture of patient safety in many ways.

First of all, if people are afraid to report, then we won’t learn what we need to learn to prevent errors. It also gives us a false low estimate of medical errors. We depend primarily on nurses to report errors, and that’s how we assess if we have made any progress. If 37% of nurses report that staff don’t feel free to question authority, that is a major problem in providing safe care.

HEH: How important is nurse staffing to patient safety?

Aiken: We found that it is a major factor. This particular measure that we use in the work environment has five subscales. The most important subscale that drives nurse assessments of the overall quality of the work environment is staffing adequacy. [Our research has shown] that every additional patient that a nurse takes is associated with about a 7% increase in mortality.2

Most of that represents preventable mortality that is somehow associated with insufficient care that allows bad things to happen to patients. Staffing is definitely associated with safety.

HEH: You conclude that work culture is more important than a patient safety culture.

Aiken: What we found in our study is that the work environment is a better predictor of patient safety than a culture of patient safety because it is more inclusive. A culture of patient safety is a part of the overall work environment. We were the major researchers who evaluated the California nurse-patient ratios, which all of our research shows definitely worked well and were in the public interest.

HEH: Why has the importance of work environment to patient safety been so difficult to communicate?

Aiken: I don’t think there has been a connection in the minds of hospital administrators and even their patient safety staff. I don’t think they connect the nurse work environment and the high risk of nurse burnout with patient safety. They are obviously highly connected.

That was one reason we wrote this paper. We are trying to get them to understand that having a safe level of nurse staffing and a work environment that allows nurses to spend most of their time in direct care of patients is a patient safety intervention. It is probably the most powerful patient safety intervention that they could possibly be working on.


  1. Kohn LT, Corrigan JM, Donaldson MS, editors. To Err is Human: Building a Safer Health System. Washington, DC: National Academies Press, Institute of Medicine; 1999.
  2. Page A, editor. Keeping Patients Safe: Transforming the Work Environment of Nurses. Washington, DC. National Academies Press, Institute of Medicine; 2004.
  3. Aiken LH, Sloane DM, Barnes H, et al. Nurses’ And Patients’ Appraisals Show Patient Safety In Hospitals Remains A Concern. Health Affairs 2018; 37(11): 1744-1751.
  4. Olds DM, Aiken LH, Lake ET. Association of Nurse Work Environment and Safety Climate on Patient Mortality: A Cross-sectional Study. International Jrl Nurs Studies 2017;74:155-161.