Hospitals with low nurse staffing levels tend to have higher

rates of poor patient outcomes such as pneumonia, shock,

cardiac arrest, and urinary tract infections, according to

research funded by the Agency for Healthcare Research and

Quality (AHRQ) and others. Yet increasing staffing levels is

not an easy task. Major factors contributing to lower

staffing levels include the needs of today’s higher acuity

patients for more care and a nationwide gap between the

number of available positions and the number of registered

nurses (RNs) qualified and willing to fill them. This is

evident from an average vacancy rate of 13 percent. 

This report summarizes the findings of AHRQ-funded and

other research on the relationship of nurse staffing levels to

adverse patient outcomes. This valuable information can be

used by decisionmakers to make more informed choices in

terms of adjusting nurse staffing levels and increasing nurse

recruitment while optimizing quality of care and improving

nurse satisfaction. 

Background

Periods of high vacancy rates for RNs in hospitals have

come and gone, but the current shortage is different.

According to a 2002 report by the workforce commission

of the American Hospital Association, the nursing shortage

“reflects fundamental changes in population demographics,

career expectations, work attitudes and worker

dissatisfaction.”1 In fact, the present situation may well

continue over the next two decades. A Federal Government

study predicts that hospital nursing vacancies will reach

800,000, or 29 percent, by 2020.2 The number of nurses is

expected to grow by only 6 percent by 2020, while demand

for nursing care is expected to grow by 40 percent. 

The most recent research shows a jump of 100,000 RNs, or

9 percent, in the hospital RN workforce between 2001 and

2002 because of increased demand, higher pay, and a

weakening economy. However, since almost all of the

Hospital Nurse Staffing and Quality of Care

Making a Difference

Lower levels of hospital nurse staffing are associated with

more adverse outcomes...Page 3

Patients have higher acuity, yet the skill levels of the

nursing staff have declined...Page 5

Higher acuity patients and added responsibilities increase

nurse workload...Page 5

Avoidable adverse outcomes such as pneumonia can raise

treatment costs by up to $28,000...Page 6

Hiring more RNs does not decrease profits... Page 6

Higher levels of nurse staffing could have positive impact

on both quality of care and nurse satisfaction...Page 7

Issue #14 March 2004

Author: Mark W. Stanton, M.A.

Managing Editor: Margaret Rutherford

Design and Production: Frances Eisel

Suggested citation: Stanton MW, Rutherford MK. Hospital nurse staffing and quality of care. Rockville (MD): Agency for Healthcare Research and Quality; 2004.

Research in Action Issue 14. AHRQ Pub. No. 04-0029.

RESEARCH

IN ACTION

Agency for Healthcare Research and Quality • www.ahrq.gov
increase came from RNs over age 50 who returned to the

workforce and a greater influx of foreign-born RNs, this

does not alter the structural features in the long term: the

aging of the nurse population and the increasing

unwillingness of young women to consider nursing as a

profession.3

Today’s difficulties are further complicated by other changes

in hospital care, such as new medical technologies and a

declining average length of stay, that have led to increases in

the amount of care required by patients while they are in the

hospital. New medical technologies allow many less

seriously ill patients who previously would have received

inpatient surgical care to receive care in outpatient settings.

Also, patients who in the past would have continued the

early stages of their recovery in the hospital, today are

discharged to skilled nursing facilities or to home. During

the period 1980-2000, the average length of an inpatient

hospital stay fell from 7.5 days to 4.9 days.4 An important

consequence of these changes is that hospitals have a higher

overall concentration of sick people who need more care. 

Various groups, including the American Hospital

Association, the Joint Commission on the Accreditation of

Healthcare Organizations, and the Institute of Medicine

(IOM), have expressed their concerns about the evolving

nursing crisis. The IOM issued a report in 1996 that

recognized the importance of determining the appropriate

nurse-patient ratios and distribution of skills for ensuring

that patients receive quality health care.5 Its report

highlighted the fact that research on the relationship between

the level of staffing by nurses in hospitals and patients’

outcomes has been inconclusive. The IOM’s analysis of

staffing and quality of care in hospitals concluded by calling

for “a systematic effort ... at the national level to collect and

analyze current and relevant data and develop a research and

evaluation agenda so that informed policy development,

implementation and evaluation are undertaken in a timely

manner.” To begin to meet that need, AHRQ-funded research

and other research have pursued a number of different paths. 

Hospital nurse staffing and nursing-sensitive

outcomes

Hospital nurse staffing is a matter of major concern because

of the effects it can have on patient safety and quality of

care. Nursing-sensitive outcomes are one indicator of quality

of care and may be defined as “variable patient or family

caregiver state, condition, or perception responsive to

nursing intervention.”6 Some adverse patient outcomes

potentially sensitive to nursing care are urinary tract

infections (UTIs), pneumonia, shock, upper gastrointestinal

bleeding, longer hospital stays, failure to rescue, and 30-day

mortality.a Most research has focused on adverse rather than

positive patient outcomes for the simple reason that adverse

outcomes are much more likely to be documented in the

medical record.

2 www.ahrq.gov

The nurse workforce and nurse staffing levels

The nurse workforce consists of licensed nurses—registered nurses (RNs) and licensed practical nurses (LPNs)—and nurses’ aides

(NAs). Both RNs and LPNs are licensed by the State in which they are employed. RNs assess patient needs, develop patient care plans,

and administer medications and treatments; LPNs carry out specified nursing duties under the direction of RNs. Nurses’ aides typically

carry out nonspecialized duties and personal care activities. RNs, LPNs, and nurses’ aides all provide direct patient care.

RNs have obtained their education through three different routes: 3-year diploma programs, 2-year associate degree programs, and 4-

year baccalaureate degree programs. Almost a third of all RNs have a baccalaureate degree, and 7.6 percent of hospital nurses have

advanced practice credentials (either a master’s or doctoral degree). LPNs receive 12-18-month training programs that emphasize

technical nursing tasks. Nurses’ aides are not licensed but many acquire certified nurse aide or nursing assistant (CNA) status after

proving they have certain skills related to the requirements of particular positions.

Nurse staffing is measured in one of two basic ways: 

• Nursing hours per patient per day. 

• The nurse to patient ratio. 

“Nursing hours” may refer to RNs only; to RNs and LPNs; or to RNs, LPNs, and nurses’ aides. 

a “Failure to rescue” is defined as the death of a patient with a lifethreatening complication for which early identification by nurses and

medical and nursing interventions can influence the risk of death. 
A broad array of research on this topic has found an

association between lower nurse staffing levels and higher

rates of some adverse patient outcomes. A new evidence

report entitled The Effect of Health Care Working

Conditions on Patient Safety, produced by an AHRQfunded Evidence-based Practice Center (EPC), reviewed 26

studies on the relationship between nurse staffing levels and

measures of patient safety.b Most of the studies examined

nurse staffing levels and adverse occurrences in the hospital

setting, including in-hospital deaths and nonfatal adverse

outcomes such as nosocomial infections, pressure ulcers, or

falls. The EPC’s researchers found that lower nurse-topatient ratios were associated with higher rates of nonfatal

adverse outcomes.7 This was true at both the hospital level

and the nursing unit level. With regard to in-hospital deaths,

however, the evidence does not consistently show that lower

nurse staffing levels are associated with higher mortality. 

Lower staffing levels are linked to higher adverse

outcome rates

The EPC report included five studies funded by AHRQ that

examined the relationship between adverse patient

outcomes and hospital nurse staffing. All five studies found

at least some association between lower nurse staffing

levels and one or more types of adverse patient outcomes. 

How often do such adverse “nursing-sensitive” patient

outcomes occur in hospital care? Different studies report

varying adverse event rates, which vary by the type of

patient (medical or surgical) as well as other factors. For

example, UTIs occur in from 1.9 percent to 6.3 percent of

surgical patients and pneumonia in 1.2 percent to 2.6

percent of surgical patients.8-10

The largest of these studies on nurse staffing (jointly

funded by AHRQ, the Health Resources and Services

Administration, the Centers for Medicare & Medicaid

Services, and the National Institute of Nursing Research)

examined the records of 5 million medical patients and 1.1

million surgical patients who had been treated at 799

hospitals during 1993.6,8 Among the study’s principal

findings:

• In hospitals with high RN staffing, medical patients had

lower rates of five adverse patient outcomes (UTIs,

pneumonia, shock, upper gastrointestinal bleeding, and

longer hospital stay) than patients in hospitals with low

RN staffing.c

• Major surgery patients in hospitals with high RN

staffing had lower rates of two patient outcomes (UTIs

and failure to rescue).

• Higher rates of RN staffing were associated with a 3- to

12-percent reduction in adverse outcomes, depending on

the outcome. 

• Higher staffing at all levels of nursing was associated

with a 2- to 25-percent reduction in adverse outcomes,

depending on the outcome. 

Table 1 illustrates some of the major findings. For example,

the researchers found that medical patients in hospitals with

high RN staffing were 4-12 percent less likely to develop

UTIs than medical patients in the comparison group.

www.ahrq.gov 3

Table 1. Percent reduction in rates of outcomes among medical

patients in hospitals with high nurse staffing (75th percentile)

compared to the rates in hospitals with low nurse staffing (25th

percentile)

Amount by which rates are lower for:

High staffing, 

Outcome in High RN all levels

medical patients staffing (RNs, LPNs, aides)

Urinary tract infection 4-12% 4-25%

Upper gastrointestinal bleeding 5-7% 3-17%

Hospital-acquired pneumonia 6-8% 6-17%

Shock or cardiac arrest 6-10% 7-13%

Note: Difference is expressed as a range of values (e.g., 4-12 percent) because several

statistical models were used in evaluating the relationship between nurse staffing levels

and each adverse event.

Source: Needleman J, Buerhaus P, Mattke S, et al. Nurse-staffing levels and patient outcomes in hospitals. Final report for Health Resources and Services Administration.

Contract No. 230-99-0021. 2001. Harvard School of Public Health, Boston, MA.

b In order to improve the quality and delivery of health care services,

AHRQ has sponsored a series of evidence reports that are based on

rigorous, comprehensive reviews of relevant scientific literature. These

reports are developed and written by outside research and academic

organizations designated as Evidence-based Practice Centers (EPCs). The

reports’ emphasis is on explicit and detailed documentation of methods,

rationale, and assumptions. The goal of these reports is to provide the

scientific foundation that public and private organizations can use to

develop their own clinical practice guidelines, quality measures, review

criteria, and other tools to improve the quality and delivery of health care

services

c This study measured RN staffing as hours per day and as the RN

proportion of nursing hours. Hospitals with higher hours of RN staffing

(75th percentile) had an average of 9.1 hours of inpatient RN nursing per

patient day, while those with lower RN staffing (25th percentile) had an

average 6.4 hours of inpatient RN nursing per patient day. Hospitals with

a higher proportion of RN staffing (75th percentile) had an average of 75

percent of inpatient nursing hours provided by RNs, while those with

lower RN staffing (25th percentile) had an average of 62 percent of

nursing hours provided by RNs. 
Medical patients in hospitals with high levels of total nurse

staffing (RNs, LPNs, and aides) were 4-25 percent less

likely to develop UTIs than patients in the comparison

group. 

A similar analysis was performed for the smaller group of

surgical patients (Table 2). Surgical patients in hospitals

with high RN staffing had a 5-6 percent lower rate of UTIs

and a 4-6 percent lower rate of failure to rescue than

surgical patients in the comparison group.d

A second study, funded jointly by AHRQ and the National

Science Foundation, examined licensed nurse staffing (RNs

and LPNs) and adverse outcomes among both medical and

surgical patients in Pennsylvania acute-care hospitals.11 It

found a lower incidence of nearly all adverse outcomes it

studied in hospitals with more licensed nurses. For

example, a 10-percent increase in the number of licensed

nurses is estimated to decrease lung collapse by 1.5 percent,

pressure ulcers by 2 percent, falls by 3 percent, and UTIs

by less than 1 percent. Also, with a 10-percent higher

proportion of licensed nurses, there was a 2-percent lower

incidence of pressure ulcers.e,11

Pneumonia rates are especially sensitive to staffing

levels

Three AHRQ-funded studies found a significant correlation

between lower nurse staffing levels and higher rates of

pneumonia.

• The first study found that adding half an hour of RN

staffing per patient day could reduce pneumonia in

surgical patients by over 4 percent.12 This study covered

589 hospitals in 10 States during 1993.

• A second study by the same researchers also found that

fewer RN hours per patient day were significantly

correlated with a higher incidence of pneumonia.13 The

study examined administrative data on post-surgical

patients in 11 States during 1990-96. 

• A study of nurse staffing levels and adverse outcomes in

California found that an increase of 1 hour worked by

RNs per patient day was associated with an 8.9-percent

decrease in the odds of a surgical patient’s contracting

pneumonia.8

• This study also found that a 10-percent increase in RN

proportion was associated with a 9.5-percent decrease in

the odds of pneumonia. 

The researchers in the California study believe that the

strong relationship between RN staffing and pneumonia can

be attributed to the heavy responsibility RNs have for

respiratory care in surgical patients. This study examined

the effects of nurse staffing on adverse outcomes in 232

acute care hospitals from 1996 to 1999.f Unlike many

earlier studies, the California study included only adverse

outcomes that were not present at admission.7

4 www.ahrq.gov

Table 2. Percent reduction in rates of outcomes among surgical

patients in hospitals with high nurse staffing (75th percentile)

compared to the rates in hospitals with low nurse staffing (25th

percentile)

Amount by which rates are lower for:

High staffing, 

Outcome in High RN all levels

surgical patients staffing (RNs, LPNs, aides)

Urinary tract infection 5-6% 3-14%

Failure to rescue 4-6% 2-12%

Hospital-acquired pneumonia 11% 19%

Note: Difference is expressed as a range of values (e.g., 2-12 percent) because several

statistical models were used in evaluating the relationship between nurse staffing levels

and each adverse event.

Source: Needleman J, Buerhaus P, Mattke S, et al. Nurse-staffing levels and patient outcomes in hospitals. Final report for Health Resources and Services Administration.

Contract No. 230-99-0021. 2001. Harvard School of Public Health, Boston, MA.

d Surgical patients overall had lower rates of adverse outcomes than

medical patients, perhaps because they are healthier. Also, the smaller

number of surgical patients in the study may have made it more difficult

to detect associations.

e Nurse staffing was measured in two ways: (1) the ratio of licensed

nurses (RNs + LPNs) to the patient load (with and without adjustments

for patient acuity) and (2) the proportion of licensed nurses to the total

nursing staff (RNs, LPNs, NAs). The adverse outcomes selected for

study were “either caused by or not prevented by medical management”

based on criteria used by the Harvard Medical Practice Study.

f Nurse staffing was measured in three ways: all hours (the total number

of productive hours worked by all nursing personnel per patient day), RN

hours (the total number of productive hours worked by registered nurses

per patient day), and RN proportion (RN hours divided by all hours).
www.ahrq.gov 5

Mortality may be associated with staffing levels

Although studies overall are not consistent in demonstrating

that higher nursing workload is associated with higher

patient mortality, two recent AHRQ-funded studies have

found that 30-day mortality and an increase in the

likelihood of failure to rescue are higher when nurse

staffing levels are lower.

• The first study found that each additional surgical

patient per nurse was associated with a 7-percent higher

likelihood of dying within 30 days of admission and a 7-

percent higher likelihood of failure to rescue. In the 168

hospitals with a mean patient-to-nurse ratio ranging

from 4:1 to 8:1, 4,535 of 232,342 patients died within

30 days of being admitted. If the patient-nurse ratio had

been as low as 4:1 in the 168 hospitals, then possibly

only 4,000 patients might have died, and had the ratio

been as high as 8:1, more than 5,000 might have died.14

• A second study found that 30-day mortality rates among

AIDS patients were lower where there was both a higher

nurse-patient ratio and an AIDS specialty physician

service. For example, the study found that an increase of

0.25 nurse per patient day would produce a 20-percent

decrease in 30-day mortality.15

Nurse staffing may be measured by educational level as

well as by the number and proportion of RNs in the nursing

staff. A third AHRQ-funded study found that a 10-percent

increase in the proportion of nurses holding a bachelor’s

degree was associated with a 5-percent decrease in both the

likelihood of surgical patients dying within 30 days of

admission and the odds of failure to rescue.16

Nurse workload and job dissatisfaction 

The studies discussed above have documented the

connection between lower levels of nurse staffing and

higher rates of adverse events. Complementing those

studies are a number of other studies addressing the

growing nurse workload and rising rates of burnout and job

dissatisfaction. One study, jointly funded by AHRQ and the

National Science Foundation, examined the relationship

between nurse staffing and hospital patient acuity (the

average severity of illness of the inpatient population) in

Pennsylvania hospitals.11 Acuity determines how much care

a patient needs: the higher the acuity, the more care is

required. This study found: 

• A 21-percent increase in hospital patient acuity between

1991 and 1996.

• No net change in the number of employed licensed

nurses. 

• A total decrease of 14.2 percent in the ratio of licensed

nursing staff to acuity-adjusted patient days of care

because of the increase in patient acuity.g

In addition, the skill mix of the nursing staff shifted as

hospitals increased the number of nurses’ aides. As a result,

RNs acquired more supervisory responsibilities that took

them away from the bedside at a time when their patients

needed more bedside nursing care.h

Concerns arising from increased patient acuity and the

assumption of additional supervisory responsibilities appear

to be directly related to job dissatisfaction expressed by

nurses in various opinion surveys. For example, a 1999

AHRQ-funded study surveyed 13,471 nurses in

Pennsylvania. Among the principal findings:

• Among those surveyed, 40 percent were dissatisfied

with their jobs. This is much higher than the 10-15

percent levels of dissatisfaction registered by other

professionals and by workers in general in the United

States.

• Only 35.7 percent of the nurses surveyed described the

quality of care on their unit as excellent.

• A large proportion of nurses, 44.8 percent, said that

there had been deterioration in the quality of care in

their hospital during the past year. 

• Of the nurses surveyed, 83 percent reported that there

had been an increase in the number of patients assigned

to them during the previous year. 

• Only 34.4 percent of nurses believed that there are

enough RNs to provide high-quality care. 

g “Patient days of care” are equal to the total yearly number of patients in

the hospital multiplied by the number of days they spent in the hospital.

“Adjusted” patient days of care take into account the outpatient care

provided by the hospital because staffing data do not distinguish between

in- and outpatient staff. Acuity-adjusted patient days of care, in addition

to accounting for outpatient care, adjust for each patient’s illness by

assigning it a MediQual severity score. This score indicates the presence

or absence of a major or minor morbidity as measured by MedisGroupsdefined methodology.

h An AHRQ-funded study of 570 hospitals in 13 States found a slight

increase in the RN hours per adjusted patient day, from 5.84 in 1990 to

6.56 in 1996. However, the researchers were uncertain about the

significance of this change since limitations in the database did not allow

them to differentiate between direct-care RNs and RNs working in

indirect or administrative capacities. Also, the study did not measure

changes in hospital acuity. 
• Only 33.4 percent believed that there are enough staff

to get the work done. 

In addition to increased patient acuity, nurse perceptions of

inadequate staffing levels are probably related to their

being expected to perform non-nursing tasks such as

delivering and retrieving food trays; housekeeping duties;

transporting patients; and ordering, coordinating, or

performing ancillary services.17,18

Cost impacts of adverse events

While inadequate staffing levels place heavy burdens on

the nursing staff and adverse events are painful for

patients, there is also a considerable financial cost to be

considered. An AHRQ-funded study found that all adverse

events studied (pneumonia, pressure ulcer, UTI, wound

infection, patient fall/injury, sepsis, and adverse drug

event) were associated with increased costs. For example,

the cost of care for patients who developed pneumonia

while in the hospital rose by 84 percent. Treating

pneumonia raised total treatment costs by $22,390-

$28,505, while the length of stay increased 5.1-5.4 days

and the probability of death rose 4.67-5.5 percent.8

Pressure ulcers, another category of adverse patient event

sensitive to nursing care, are estimated to cost $8.5 billion

per year.19

Strategies for improvement 

Many stakeholders within the health care system,

especially Federal and State governments, hospitals and

hospital organizations, nurse associations, foundations,

and accreditation organizations, are aware of the lack of

qualified nursing staff and related problems and are

actively seeking solutions. On the Federal level, in 2002,

Congress passed the Nurse Reinvestment Act, which has

put into effect various measures to improve the

recruitment and retention of nurses. The Act establishes a

National Nurse Service Corps to give scholarships and

loans to nursing students if they are willing to serve in

hospitals with critical shortages of nurses for a 2-year

period. It also sets up a loan forgiveness program for

nurses receiving advanced degrees who will teach at

nursing schools. In addition, it offers nurses continuing

education, geriatric training, and “career ladder” programs

for job advancement, as well as internship and mentor

programs.

State governments have also gotten involved. For example,

the State of California has legislated minimum nurse

staffing ratios and a number of other States are

considering similar legislation. However, one analysis

suggests that such measures may generate opportunity

costs that are not easily measured and that may outweigh

their benefits.i,20 For example, hospitals may cut spending

for other personnel, such as unlicensed caregivers,

housekeepers, and other support staff. The amount of nonnursing work performed by RNs in inpatient units could

increase, and investments in medical technology and

facilities to improve the quality of care could be deferred. 

Hospitals that increase their nurse staffing ratios either

across all units or within individual units have reason to be

concerned about the impact of such steps on their

finances. However, a new study finds that increased

staffing of RNs does not significantly decrease a hospital’s

profit, even though it boosts the hospital’s operating costs.

A 1-percent increase in RN full-time equivalents increased

operating expenses by about 0.25 percent but resulted in

no statistically significant effect on profit margins. In

6 www.ahrq.gov

AHRQ-Funded Research on Nurse Staffing and

Quality of Care

Nurse Staffing and Quality of Care. Grant No. HS09958. Harvard

University. (Cofunded by Health Resources and Services

Administration, Centers for Medicare & Medicaid Services,

National Institute of Nursing Research). This project examined

the relationship between the amount of care provided by hospital

nurses and patient outcomes. 

Nurse Staffing and Quality of Hospital Patient Care. Grant No.

HS09991. University of Central Florida. This project examined

changes in licensed nurse staffing in Pennsylvania hospitals from

1991 to 1997 and assessed the relationship of licensed nurse

staff to patient adverse events.

Outcomes of Hospital Dedicated AIDS Units. Grant No. HS08603.

University of Pennsylvania. This project compared differences in

AIDS patients’ 30-day mortality and satisfaction with care in

dedicated AIDS units, magnet hospitals, and scattered-bed units

in hospitals with and without dedicated AIDS units.

i Opportunity cost includes not only the money spent in buying

something, but also the economic benefits forgone because that

particular thing was bought and thus something else can no longer be

bought. 
www.ahrq.gov 7

contrast, higher levels of non-nurse staffing caused higher

operating expenses as well as lower profits.21

The National Quality Forum, a private, not-for-profit group

of public and private health care organizations created to

develop and implement a national strategy for health care

quality measurement and reporting, has been actively

developing national voluntary consensus standards for

nursing-sensitive performance measurement. Such measures

can help to evaluate the extent to which the lack of qualified

nursing staff is affecting the quality of health care. They can

also help to identify opportunities to improve nursing

performance.22

In a recent report on strategies to address the evolving

nursing crisis, the Joint Commission on the Accreditation of

Healthcare Organizations proposed bolstering the nursing

educational infrastructure through team training in nursing

education, enhancing support of nursing orientation, inservice and continuing education in hospitals, and creating

nursing career ladders based on educational level and

experience. It also supports adopting the characteristics of

“magnet hospitals,” such as setting staffing levels based on

nurse competency and skill mix relative to patient mix and

acuity.j In addition, it proposes establishing financial

incentives for health care organizations to invest in nursing

services.23

In its latest report on patient safety, issued in draft form in

November 2003, the Institute of Medicine identified

workforce deployment patterns in the typical work

environment of nurses as contributing to many serious

threats to patient safety. Among various measures it called

for was the involvement of the direct-care nursing staff in

determining and evaluating the approaches used to

determine appropriate unit staffing levels for each shift.24

The patient safety initiative and hospital nurse

staffing 

Hospital nurse staffing has an important relationship to

patient safety and quality of care. Under a broad initiative

focusing on patient safety issues, AHRQ has funded a group

of projects on understanding the impact of working

conditions on patient safety.k Seven projects ($2.5 million)

related to hospital nurse staffing are included in this

category. Researchers are examining the critical issues of

how staffing, fatigue, stress, sleep deprivation,

organizational culture, shift work, and other factors can lead

to errors. These issues—which have been studied extensively

in aviation, manufacturing, and other industries—have not

been closely studied in health care settings. 

Thus far, under this initiative, three studies have been

completed. One study examined the effects of nurse staffing

on adverse outcomes, morbidity, mortality, and medical

costs.8 A second study developed an evidence report with an

objective of identifying and summarizing evidence from the

scientific literature on the effects of health care working

conditions on patient safety. In addition to workforce

staffing, it discussed workflow design, personal and social

working conditions, the physical environment, and

organizational factors.7 A third study of the work

environment for nurses and patient safety identified key

aspects of the work environment for nurses—including

extended hours and workload—that likely have an impact on

patient safety, and identified potential improvements in

health care working conditions that could result in enhanced

patient safety.24

Other ongoing studies include:

• An examination of the impact of unit-level nurse

workload on patient safety. This project is assessing the

relationship between medical errors and daily changes in

the working conditions in hospitals—including nurse

staffing ratios, workload, and skill mix. Results are

expected in early 2004.

• A study of hospital nurses’ working conditions and

patient outcomes. This project is examining the

relationship between the occurrence of adverse patient

outcomes and nursing care delivery models, job strain,

risk of injury, and hospitals’ use of overtime and contract

nurses. 

• A study of the impact of nurses’ working conditions on

medication safety. The aim of this study is to describe

how nurses’ working conditions, workload (e.g., shift

length and patient assignment), actions taken (e.g.,

adherence to standards and actions that prevent adverse

drug effects), and organizational variables affecting

nurses are related to the safety and quality of the care

they provide. The working conditions under study

include physical environment, safety climate, automation,

and staffing levels.

j Magnet hospitals must meet stringent quantitative and qualitative

standards that define the highest quality of nursing practice and patient

care.

k For more information about this program, see

http://www.ahrq.gov/qual/newgrants/working.htm.
• A study of the relation of hospital workload to patient

safety. This study is examining the association between

hospital activity/workload and rates of adverse drug

events to assess whether the workload should be limited

or the processes during times of high workload pressure

should be reengineered to improve patient safety.

Investigators are also developing new methods for

identifying adverse events using electronic medical

records.

Conclusion

The largest of the studies discussed here found significant

associations between lower levels of nurse staffing and

higher rates of pneumonia, upper gastrointestinal bleeding,

shock/cardiac arrest, urinary tract infections, and failure to

rescue.6,7 Other studies found associations between lower

staffing levels and pneumonia, lung collapse, falls, pressure

ulcers, thrombosis after major surgery, pulmonary

compromise after surgery, longer hospital stays, and 30-day

mortality. However, researchers stress that, at present, such

“nursing-sensitive” adverse outcomes should be viewed

more as indicators or sentinel outcomes than as measures of

the full impact of nurse staffing on patient outcomes. 

Research findings indicating what minimal nurse staffing

ratios should be either within the hospital or within its

various subunits are not available. Researchers believe that

more accurate and consistent measures of acuity and

quality and more complete data on staffing for all types of

nursing personnel are needed to explain the complex

relationship between nurse staffing and the quality of care.13

The findings thus far can have a positive impact if used to

educate and inform interested parties on how quality of

care is changing and how it is linked to the contributions of

nurses. 

Some hospitals may choose to increase nurse staffing

levels. According to the authors of one study: “The

implications of doing nothing to improve nurse staffing in

low staffed hospitals are that a large number of patients will

suffer avoidable adverse outcomes and patients will

continue to incur higher costs than are necessary.”19 Finally,

policymakers may want to monitor developments in nurse

staffing issues closely in order to determine if additional

legislative changes are needed to increase nursing supply

and reduce adverse patient outcomes. 

References

1. American Hospital Association, Commission on

Workforce for Hospitals and Health Systems. In our

hands: how hospital leaders can build a thriving

workforce. May 2002. 

2. Health Resources and Services Administration, Bureau

of Health Professions, National Center for Health

Workforce Analysis. Projected supply, demand, and

shortages of registered nurses: 2000-2020. HRSA Web

site: http://bhpr.hrsa.gov/healthworkforce/

reports/rnproject/default.htm. 

3. Buerhaus PI, Staiger DO, Auerbach DI. Is the current

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* AHRQ-funded/sponsored research

www.ahrq.gov 9

www.ahrq.gov 11

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13 Dental Care: Improving Access and Quality AHRQ 03-0040

12 Advance Care Planning: Preferences for Care at the End of Life AHRQ 03-0018

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8 Prescription Drug Therapies: Reducing Costs and Improving AHRQ 02-0045

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7 Improving Treatment Decisions for Patients with Community- AHRQ 02-0033

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6 Medical Informatics for Better and Safer Health Care AHRQ 02-0031

5 Expanding Patient-Centered Care to Empower Patients and AHRQ 02-0024

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4 Managing Osteoarthritis: Helping the Elderly Maintain Function AHRQ 02-0023

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