Chapter 3. An Overview of To Err is Human: 

Re-emphasizing the Message of Patient Safety 

Molla Sloane Donaldson

Introduction 

On November 29, 1999, the Institute of Medicine (IOM) released a report called To Err is 

Human: Building a Safer Health System.

1

 The IOM released the report before the intended date 

because it had been leaked, and one of the major news networks was planning to run a story on 

the evening news.2

 Media throughout the country recognized this opportunity for a headline story 

describing a very large number of hospital deaths from medical errors —possibly as great as 

98,000 per year. The problem in other care settings was unknown, but suspected to be great. 

The search was on to find out who was to blame and how to fix the problem. Congressional 

hearings were subsequently held. Governmental agencies, professional groups, accrediting 

organizations, insurers, and others quickly responded with plans to define events and develop 

reporting systems. Health care organizations were put on the defensive. Recognizing that 

individual accountability is necessary for the small proportion of health professionals whose 

behavior is unacceptable, reckless, or criminal, the public held organizational leadership, boards, 

and staff accountable for unsafe conditions. Yet imposing reporting requirements and holding 

people or organizations accountable do not, by themselves, make systems safer. 

What was often lost in the media attention to hospital deaths from medical errors cited by To 

Err is Human was the original intent of the IOM Committee on Quality Health Care in America, 

which developed the report. That committee believed it could not address the overall quality of 

care without first addressing a key, but almost unrecognized component of quality; which was 

patient safety. The committee’s approach was to emphasize that “error” that resulted in patient 

harm was not a property of health care professionals’ competence, good intentions, or hard work. 

Rather, the safety of care—defined as “freedom from accidental injury”3 (p. 16)—is a property of 

a system of care, whether a hospital, primary care clinic, nursing home, retail pharmacy, or home 

care, in which specific attention is given to ensuring that well-designed processes of care 

prevent, recognize, and quickly recover from errors so that patients are not harmed. 

This chapter focuses on the principles described in the IOM report, many of which can be 

mapped to what are now called safe practices4

 and all of which are valuable guides. This chapter 

is not intended to address the growing body of evidence; rather, the chapter summarizes the 

starting point—the IOM recommendations based on the literature and the knowledge of the 

committee members who developed the report. 

Moving the Focus From Errors to Safety 

Errors occur in health care as well as every other very complex system that involves human 

beings. The message in To Err is Human was that preventing death and injury from medical 

errors requires dramatic, systemwide changes.1 Among three important strategies—preventing, 

recognizing, and mitigating harm from error—the first strategy (recognizing and implementing 

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Patient Safety and Quality: An Evidence-Based Handbook for Nurses

actions to prevent error) has the greatest potential effect, just as in preventive public health 

efforts. 

The IOM committee recognized that simply calling on individuals to improve safety would 

be as misguided as blaming individuals for specific errors. Health care professionals have 

customarily viewed errors as a sign of an individual’s incompetence or recklessness. As a result, 

rather than learning from such events and using information to improve safety and prevent new 

events, health care professionals have had difficulty admitting or even discussing adverse events 

or “near misses,” often because they fear professional censure, administrative blame, lawsuits, or 

personal feelings of shame. Acknowledging this, the report put forth a four-part plan that applies 

to all who are, or will be, at the front lines of patient care; clinical administrators; regulating, 

accrediting, and licensing groups; boards of directors; industry; and government agencies. It also 

suggested actions that patients and their families could take to improve safety. 

The committee understood that need to develop a new field of health care research, a new 

taxonomy of error, and new tools for addressing problems. It also understood that responsibility 

for taking action could not be borne by any single group or individual and had to be addressed by 

health care organizations and groups that influence regulation, payment, legal liability, education 

and training, as well as patients and their families. The report called on Congress to create a 

National Center for Patient Safety within the Agency for Healthcare Research and Quality, to 

develop new tools and patient care systems that make it easier to do things right and harder to do 

things wrong. This handbook is a direct result of the implementation of those recommendations. 

Improving Safety by Understanding Error 

Every day, physicians, advance practice nurses, nurses, pharmacists, and other hospital 

personnel recognize and correct errors and usually prevent harm. Errors, defined as “the failure 

of a planned action to be completed as intended or the use of a wrong plan to achieve an 

aim,”1

 do not all result in injury or harm. Errors that do cause injury or harm are sometimes 

called preventable adverse events—that is, the injury is thought to be due to a medical 

intervention, not the underlying condition of the patient. Errors that result in serious injury or 

death, considered “sentinel events” by the Joint Commission (formerly the Joint Commission on 

Accreditation of Healthcare Organizations [JCAHO]),5

 signal the need for an immediate 

response, analysis to identify all factors contributing to the error, and reporting to the appropriate 

individuals and organizations7

 to guide system improvements. 

The key question for the IOM, as for many health professionals now, was what could be done 

to improve safety. To differentiate between individual factors and system factors, the report 

distinguished between the “sharp” end of a process in which the event occurs (e.g., 

administration of the wrong dose of medication that is fatal, a mishap during surgery) and the 

“blunt” end in which many factors (called latent conditions), which may have seemed minor, 

have interacted and led to an error.6

 These latent conditions may be attributable to equipment 

design or maintenance, working conditions, design of processes so that too many handoffs occur, 

failures of communication, and so forth.7-9 

Leape8 greatly enhanced our understanding of errors by distinguishing between two types of 

cognitive tasks that may result in errors in medicine. The first type of task occurs when people 

engage in well-known, oft-repeated processes, such as driving to work or making a pot of coffee. 

Errors may occur while performing these tasks because of interruptions, fatigue, time pressure, 

anger, distraction, anxiety, fear, or boredom. By contrast, tasks that require problem solving are 

2 
Overview of To Err is Human

done more slowly and sequentially, are perceived as more difficult, and require conscious 

attention. Examples include making a differential diagnosis and readying several types of 

surgical equipment made by different manufacturers. Errors here are due to misinterpretation of 

the problem that must be solved and lack of knowledge. Keeping in mind these two different 

kinds of tasks is helpful to understanding the multiple reasons for errors and is the first step in 

preventing them. 

People make errors for a variety of reasons that have little to do with lack of good intention 

or knowledge. Humans have many intellectual strengths (e.g., large memory capacity and an 

ability to react creatively and effectively to the unexpected) and limitations (e.g., difficulty 

attending carefully to several things at once and generally poor computational ability, especially 

when tired).12 Improving safety requires respecting human abilities by designing processes that 

recognize human strengths and weaknesses. 

There are many opportunities for individuals to prevent error. Some actions are clinically 

oriented and evidence-based: communicating clearly to other team members, even when 

hierarchies and authority gradients seem to discourage it; requesting and giving feedback for all 

verbal orders; and being alert to “accidents waiting to happen.” Other opportunities are broader 

in focus or address the work environment and may require clinical leadership and changing the 

workplace culture: simplifying processes to reduce handoffs and standardizing protocols; 

developing and participating in multidisciplinary team training; involving patients in their care; 

and being receptive to discussions about errors and near misses by paying respectful attention 

when any member of the staff challenges the safety of a plan or a process of care. 

However, large, complex problems require thoughtful, multifaceted responses by individuals, 

teams, and organizations. That is, preventing errors and improving safety require a systems 

approach to the design of processes, tasks, training, and conditions of work in order to modify 

the conditions that contribute to errors. Fortunately, there is no need to start from scratch. The 

IOM report included some guidance based on what was known at the time, and other specific 

evidence has accumulated since then that can be put in practice today. Designing for safety 

requires a commitment to safety, a thorough knowledge of the technical processes of care, an 

understanding of likely sources of error, and effective ways to reduce errors. 

A Report From the Trenches—Systems, not Shame 

Nurses sometimes comment: 

• “We are really short-staffed. Sometimes I am so busy and distracted that I am sure I must 

make mistakes when calculating the doses of meds. I haven’t killed anyone, but I know when 

I’ve made a mistake. How can I make sure I don’t make errors?” 

• “I was supposed to administer chemotherapy to a patient. Even though I tried hard, I couldn’t 

figure out from the chart what kind of cancer the patient had. What can I do to make sure this 

sort of thing doesn’t happen again?” 

• “There is a piece of equipment on our unit that is an accident waiting to happen. The 

experienced staff knows about it and has learned how to work around it, but what happens 

when new staff are assigned?” 

These types of questions are by no means unusual. Partly because of its sheer complexity and 

the number of different individuals with different training and approaches, health care is prone to 

harm from errors—especially in operating rooms, intensive care units (ICUs), and emergency 

3 
Patient Safety and Quality: An Evidence-Based Handbook for Nurses

departments where there is little time to react to unexpected events—and consequences can be very 

serious. Although most early studies focused on the hospital setting, medical errors present a 

problem in all settings, including outpatient surgical centers, physician offices and clinics, nursing 

homes, and the home, especially when patients and families are asked to use increasingly 

complicated equipment. 

Patients should not be harmed by the health care system that is supposed to help them, but the 

solution does not lie in assigning blame or urging health professionals to be more careful. In what 

seems to be a simple example, an ICU nurse was wheeling a patient on a gurney to radiology when 

his knee struck a fire extinguisher hanging on the wall, resulting in the patient needing extra care. 

In response, the nurse may have been scolded by her supervisor and told to be more careful, or 

punished in some other way; everyone would feel the problem had been solved. Yet, would that 

make the hospital safer? Would it prevent other events that are similar but slightly different in 

circumstances from happening with other staff and patients in other units? The answer is an 

emphatic no. 

Improving safety, arises from attention to the often multiple latent factors that contribute to 

errors and in some cases, to injury. In the above example, such factors included: 1) the nurse 

having to move the patient herself because transport had never arrived; 2) a change in hospital 

policy, so that only one instead of two people guide gurneys; 3) the failure to mount the fire 

extinguisher in a recessed niche; 4) the decision to transport a seriously ill patient rather than 

having mobile equipment come to him, requiring extra “handoffs” and opportunities for injury; and 

5) poor gurney design, making steering difficult, and possibly still other factors. 

The IOM’s Four-Part Message 

The IOM committee sought what could be learned from other disciplines and applied in 

health care by clinical and administrative leadership. It described actions that health care 

professionals can take now in their own institutions, whether they are new trainees, experienced 

clinical leaders, or instructors. The major thrust of the report was a four-part plan, intended to 

create financial and regulatory incentives to create a safer health care system and a systematic 

way to integrate safety into the process of care (the focus of this chapter). The four parts of the 

IOM recommendations are described below: 

♦ Part 1: National Center for Patient Safety – The IOM recommended the creation of a 

National Center for Patient Safety in the U.S. Department of Health and Human Services’s 

Agency for Healthcare Research and Quality (AHRQ), because health care is a decade or 

more behind other high-risk industries in its attention to ensuring basic safety, establishing 

national safety goals, tracking progress in meeting them, and investing in research to learn 

more about preventing mistakes. This center would also serve as a clearinghouse and source 

of effective practices that would be shared broadly. 

♦ Part 2: Mandatory and Voluntary Reporting Systems – To learn about medical care 

associated with serious injury or death and to prevent future occurrences, the IOM 

recommended establishing a nationwide, mandatory public reporting system, where Federal 

legislation would protect the confidentiality of certain information (e.g., medical mistakes 

that have no serious consequences). The intent was to encourage the growth of voluntary, 

confidential reporting systems so that practitioners and health care organizations could learn 

about and correct problems before serious harm occurs. 

4 
Overview of To Err is Human

♦ Part 3: Role of Consumers, Professionals, and Accreditation Groups – The IOM believed 

that fundamental change would require pressure and incentives from many directions, 

including public and private purchasers of health care insurance, regulators (including the 

Food and Drug Administration), and licensing and certifying groups. A direct result was the 

announcement of new standards on safety from the Joint Commission and a report, Safe 

Practices for Better Health Care. A Consensus Report, by the National Quality Forum.10 

♦ Part 4: Building a Culture of Safety – The IOM urged health care organizations to create 

an environment in which safety becomes a top priority. This report stressed the need for 

leadership by executives and clinicians and for accountability for patient safety by boards of 

trustees. In particular, it urged that safety principles known in other industries be adopted, 

such as designing jobs and working conditions for safety; standardizing and simplifying 

equipment, supplies and processes; and avoiding reliance on memory. The report stressed 

medication safety in part because medication errors are so frequent11 and in part because a 

number of evidenced-based practices were already known and needed wider adoption. 

Though at the time of publication, the levels of evidence for each category varied, the 

members of the committee believed that all were important places to begin to improve safety. 

The committee recognized that some actions could be taken at the national level as described 

in the recommendations contained in Parts 1–3. Yet if patient safety were really to improve, the 

committee knew it would take far more than reporting requirements and regulations. Creating 

and sustaining a culture of safety (Part 4) is needed, which would require continuing local action 

by thousands of health care organizations and the individuals working in these settings at all 

levels of authority. Hospital leadership must provide resources and time to improve safety and 

foster an organizational culture that encourages recognition and learning from errors. A culture 

of safety cannot develop without trust, keen observation, and extensive knowledge of care 

processes at all levels, from those on the front lines of health care to those in leadership and 

management positions. 

Basic Concepts in Patient Safety

Opportunities to improve safety have been drawn from numerous disciplines such as engineering, psychology, and occupational health. The IOM report brought together what had been 

learned in these fields and then applied the opportunities to health care, as described in the nine 

categories that follow. 

1. User-Centered Design 

Understanding how to reduce errors depends on framing likely sources of error and pairing 

them with effective ways to reduce them. The term “user-centered design” builds on human 

strengths and avoids human weaknesses in processes and technologies.12 The first strategy of 

user-centered design is to make things visible⎯including the conceptual model of the 

process⎯so that the user can determine what actions are possible at any moment, for example, 

how to return to an earlier step, how to change settings, and what is likely to happen if a step in a 

process is skipped. Another principle is to incorporate affordances, natural mappings, and 

constraints into health care. Although the terms are strange, their meaning can be surprisingly 

easily applied to common everyday tasks, both in and out of the workplace. 

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Patient Safety and Quality: An Evidence-Based Handbook for Nurses

An affordance is a characteristic of equipment or workspace that communicates how it is to 

be used, such as a push bar on an outward opening door that shows where to push or a telephone 

handset that is uncomfortable to hold in any but the correct position. Marking the correct limb 

for before surgery is an affordance that has been widely adopted. Natural mapping refers to the 

relationship between a control and its movement, for example, in steering a car to the right, one 

turns the wheel right. Other examples include using louder sound or a brighter light to indicate a 

greater amount. 

Constraints and forcing functions guide the user to the next appropriate action or decision. A 

constraint makes it hard to do the wrong thing. A forcing function makes it impossible to do the 

wrong thing. For example, one cannot start a car that is in gear. Forcing functions include the use 

of special luer locks for syringes and indwelling lines that have to be matched before fluid can be 

infused, and different connections for oxygen and other gas lines to prevent their being 

inadvertently switched. Removing concentrated potassium chloride from patient units is a 

(negative) forcing function because it should never be administered undiluted, and preparation 

should be done in the pharmacy. 

2. Avoid Reliance on Memory 

The next strategy is to standardize and simplify the structure of tasks to minimize the demand 

on working memory, planning, or problem-solving, including the following two elements: 

• Standardize process and equipment. Standardization reduces reliance on memory and 

allows newcomers who are unfamiliar with a given process or device to do the process or 

use a device safely. For example, standardizing device displays (e.g., readout units), 

operations, and doses is important to reduce the likelihood of error. Other examples of 

standardizing include standard order forms, administration times, prescribing protocols, 

and types of equipment. When devices or medications cannot be standardized, they 

should be clearly distinguishable. For example, one can identify look-alike, but different, 

strengths of a narcotic by labeling the higher concentration in consistent ways, such as by 

shape and prominent labeling. 

When developed, updated, and used wisely, protocols and checklists can enhance 

safety. Protocols for the use of anticoagulants and perioperative antibiotics have gained 

widespread acceptance. Laminated dosing cards that include standard order times, doses 

of antibiotics, formulas for calculating pediatric doses, and common chemotherapy 

protocols can reduce reliance on memory.13 

• Simplify key processes. Simplifying key processes can minimize problem-solving and 

greatly reduce the likelihood of error. Simplifying includes reducing the number of steps 

or handoffs that are needed. Examples of processes that can usually be simplified are 

writing an order, then transcribing and entering it in a computer, or having several people 

record and enter the same data in different databases. Other examples of simplification 

include limiting the choice of drugs and dose strengths available in the pharmacy, 

maintaining an inventory of frequently prepared drugs, reducing the number of times a 

day a drug is administered, keeping a single medication administration record, 

automating dispensing, and purchasing equipment that is easy to use and maintain. 

6 
Overview of To Err is Human

3. Attend to Work Safety 

Conditions of work are likely to affect patient safety. Factors that contribute to worker safety 

in all industries studied include work hours, workloads, staffing ratios, sources of distraction, and 

shift changes (which affect one’s circadian rhythm). Systematic evidence about the relative 

importance of various factors is growing with particular emphasis on nurse staffing.14-16

4. Avoid Reliance on Vigilance 

Individuals cannot remain vigilant for long periods of time. Approaches for reducing the 

need for vigilance include providing checklists and requiring their use at regular intervals, limiting 

long shifts, rotating staff, and employing equipment that automates some functions. The need for 

vigilance can be reduced by using signals such as visual and auditory alarms. Also, well-designed 

equipment provides information about the reason for an alarm. There are pitfalls in relying on 

automation, if a user learns to ignore alarms that are often wrong, becomes inattentive or inexpert 

in a given process, or if the effects of errors remain invisible until it is too late to correct them. 

5. Train Concepts for Teams 

People work together throughout health care in multidisciplinary teams, whether in a 

practice; for a clinical condition; or in operating rooms, emergency departments, or ICUs. In an 

effective interdisciplinary team, members come to trust one another’s judgments and expertise 

and attend to one another’s safety concerns. Team training in labor and delivery and hospital 

rapid response teams are examples. The IOM committee believed that whenever it is possible, 

training programs and hospitals should establish interdisciplinary team training. 

 

6. Involve Patients in Their Care 

Whenever possible, patients and their family members or other caregivers should be invited 

to become part of the care process. Clinicians must obtain accurate information about each 

patient’s medications and allergies and make certain this information is readily available at the 

patient’s bedside. In addition, safety improves when patients and their families know their 

condition, treatments (including medications), and technologies that are used in their care. 

At the time of discharge, patients should receive a list of their medications, doses, dosing 

schedule, precautions about interactions, possible side effects, and any activities that should be 

avoided, such as driving. Patients also need clear written information about the next steps after 

discharge, such as followup visits to monitor their progress and whom to contact if problems or 

questions arise. 

Family caregivers deserve special attention in terms of their ability to provide safe care, 

manage devices and medication, and to safely respond to patient needs. Yet they may, 

themselves, be affected by physical, health, and emotional challenges; lack of rest or respite; and 

other responsibilities (including work, finances, and other family members). 

Attention is now being given to problems resulting from lack of patient and family health 

literacy. For example, information may be too complex to absorb or in a language unfamiliar 

(even to educated and English-speaking patients)—and frightening. A simple example is rapidly 

given instructions on home care of a Foley catheter when, as often occurs, the patient is being 

7 
Patient Safety and Quality: An Evidence-Based Handbook for Nurses

discharged shortly after surgery and knows nothing about sterile technique or the design of the 

device. Another ubiquitous example is the warnings and dosage information on medication 

bottles, which many patients cannot understand how to apply. 

7. Anticipate the Unexpected 

The likelihood of error increases with reorganization, mergers, and other organization-wide 

changes that result in new patterns and processes of care. Some technologies, such as computerized physician order entry systems (CPOE), are engineered specifically to prevent error. Despite 

the best intentions of designers, however, all technology introduces new errors, even when its 

sole purpose is to prevent errors. Indeed, future failures cannot be forestalled by simply adding 

another layer of defense against failure.17-19 Safe equipment design and use depend on a chain of 

involvement and commitment that begins with the manufacturer and continues with careful 

attention to the vulnerabilities of a new device or system. Health care professionals should 

expect any new technology to introduce new sources of error and should adopt the custom of 

automating cautiously, always alert to the possibility of unintended harm, and should test these 

technologies with users and modify as needed before widespread implementation. 

8. Design for Recovery 

The next strategy is to assume that errors will occur and to design and plan for recovery by 

duplicating critical functions and by making it easy to reverse operations and hard to carry out 

nonreversible ones. If an error occurs, examples of strategies to mitigate injury are keeping 

antidotes for high-risk drugs up to date and easily accessible and having standardized, wellrehearsed procedures in place for responding quickly to adverse events. Another strategy is to 

use simulation training, where learners practice tasks, processes, and rescues in lifelike 

circumstances using models or virtual reality. 

9. Improve Access to Accurate, Timely Information 

The final strategy for user-centered design is to improve access to information. Information 

for decision-making (e.g., patient history, medications, and current therapeutic strategies) should 

be available at the point of patient care. Examples include putting lab reports and medication 

administration records at the patient’s bedside and putting protocols in the patient’s chart. In a 

broader context, information is coordinated over time and across settings. 

Conclusion 

Now, 7 years after the release of To Err is Human, extensive efforts have been reported in 

journals, technical reports, and safety-oriented conferences. That literature described the 

magnitude of problems in a variety of care settings, the efforts to make change, and the results of 

those efforts in improving patient safety. Many of those studies are referenced and discussed 

throughout this book. Other authors have written incisively about what progress has and has not 

been made in the past 7 years and the challenges in creating cultures of safety.20, 21 The greatest 

challenge we all face is to learn, use, and share better information about how to prevent harm to 

patients. 

8 
Overview of To Err is Human

Author Affiliation 

Molla Sloane Donaldson, Dr.P.H., M.S., principal, M.S.D. Healthcare; e-mail: 

molla@msdhealth.com. 

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9