Chapter 30. Nursing Workload and Patient Safety—A 

Human Factors Engineering Perspective 

Pascale Carayon, Ayse P. Gurses 

Background 

The heavy workload of hospital nurses is a major problem for the American health care 

system. Nurses are experiencing higher workloads than ever before due to four main reasons: (1) 

increased demand for nurses, (2) inadequate supply of nurses, (3) reduced staffing and increased 

overtime, and (4) reduction in patient length of stay. 

First, the demand for nurses is increasing as a result of population aging. Between 2000 and 

2020, the United States population is expected to grow by 18 percent (31 million), but the over65 population, with more health care needs, is expected to grow by 54 percent (19 million).1, 2

Second, the supply of nurses is not adequate to meet the current demand, and the shortage is 

projected to grow more severe as future demand increases and nursing schools are not able to 

keep up with the increasing educational demand.3, 4 When a nursing shortage occurs, the 

workload increases for those who remain on the job.5 Third, in response to increasing health care 

costs since the 1990s, hospitals reduced their nursing staffs and implemented mandatory 

overtime policies to meet unexpectedly high demands, which significantly increased nursing 

workloads. Fourth, increasing cost pressure forced health care organizations to reduce patient 

length of stay. As a result, hospital nurses today take care of patients who are sicker than in the 

past; therefore, their work is more intensive.6 

There are several important consequences of high nursing workload. Research shows that a 

heavy nursing workload adversely affects patient safety.7 Furthermore, it negatively affects 

nursing job satisfaction and, as a result, contributes to high turnover and the nursing shortage.8 In 

addition to the higher patient acuity, work system factors and expectations also contribute to the 

nurses’ workload: nurses are expected to perform nonprofessional tasks such as delivering and 

retrieving food trays; housekeeping duties; transporting patients; and ordering, coordinating, or 

performing ancillary services.9

 A 1998–1999 survey of more than 43,000 nurses in five countries 

found that 17 percent to 39 percent of respondents planned to leave their job within a year 

because of job demands.9

 Heavy nursing workload increases burnout and job dissatisfaction, 

which in turn contributes to high nurse turnover.10 This chapter focuses on the impact of nursing 

workload on patient safety. We first present different concepts and models of nursing workload, 

then discuss the impact of workload on patients and on nursing staff, presenting various 

mechanisms of the relationship between nursing workload and patient safety. Finally, we 

describe a human factors engineering approach on how work systems can be redesigned to 

reduce nursing workload or to minimize the negative impact of a heavy nursing workload. 

Concepts and Models of Nursing Workload 

Nursing workload measures can be categorized into four levels: (1) unit level, (2) job level, 

(3) patient level, and (4) situation level.11 These measures can be organized into a hierarchy. The 

situation- and patient-level workloads are embedded in the job-level workload, and the job-level 

1 
Patient Safety and Quality: An Evidence-Based Handbook for Nurses

workload is embedded in the unit-level workload. In a clinical unit, for example, numerous 

nursing tasks need to be performed by a group of nurses during a specific shift (unit-level 

workload). The type and amount of workload of nurses is partly determined by the type of unit 

and specialty (e.g., intensive care unit [ICU] nurse versus general floor nurse), which is the joblevel workload. When performing their job, nurses encounter various situations and patients, 

which are determinants of the situation- and patient-level workloads. 

Workload at the Unit Level 

The most commonly used unit-level workload measure is the nurse-patient ratio. The nursepatient ratio can be used to compare units and their patient outcomes in relation to nursing 

staffing. Previous research provides strong evidence that high nursing workloads at the unit level 

have a negative impact on patient outcomes.7, 12, 13 These studies’ suggestions regarding 

improving patient care are limited to increasing the number of nurses in a unit or decreasing the 

number of patients assigned to each nurse. However, it may not be possible to follow these 

suggestions due to costs and the nursing shortage. The major weakness of this type of research is 

that it conceptualizes nursing workload at a macro level, ignoring the contextual and 

organizational characteristics of a particular health care setting (e.g., physical layout, information 

technology available) that may significantly affect workload. Research should examine the 

impact on nursing workload of work factors in the health care microsystems. 

Workload at the Job Level 

According to this conceptualization, the level of workload depends on the type of nursing job 

or specialty (ICU nurse versus operating room nurse). For instance, Schaufeli and LeBlanc14

used a job-level measure of workload to investigate the impact of workload on burnout and 

performance among ICU nurses. Previous research linked job-level workload (a working 

condition) to various nursing outcomes, such as stress15, 16 and job dissatisfaction.17 Workload 

measures at the job level are appropriate to use when comparing workload levels of nurses with 

different specialties or job titles (ICU nurses versus ward nurses).18 However, workload is a 

complex, multidimensional construct, and there are several contextual factors in a nursing work 

environment (e.g., performance obstacles and facilitators) other than job title that may affect 

nursing workload.19 In other words, two medical ICU nurses may experience different levels of 

workload due to the different contextual factors that exist in each ICU. The workload at the joblevel conceptualization fails to explain the difference in the workloads of these two nurses. 

Workload at the Patient Level 

This conceptualization assumes that the main determinant of nursing workload is the clinical 

condition of the patient. Several patient-level workload measures have been developed based on 

the therapeutic variables related to the patient’s condition (e.g., Therapeutic Intervention Scoring 

System)15, 20, 21 and have been extensively discussed in the nursing literature. However, recent 

studies show that factors other than the patient’s clinical condition (e.g., ineffective 

communication, supplies not well-stocked) may significantly affect nursing workload. As with 

the previous two workload measures, patient-level workload measures have not been designed to 

measure the impact of these contextual factors on nursing workload. 

2 
Workload for Nurses

Situation-Level Workload 

To remedy the shortcomings of the three levels of measures explained above and 

complement them, we have suggested using another way to conceptualize and measure nursing 

workload based on the existing literature on workload in human factors engineering: situationlevel workload.11 In addition to the number of patients assigned to a nurse and the patient’s 

clinical condition, situation-level workload can explain the workload experienced by a nurse due 

to the design of the health care microsystem. In a previous study, we found that various 

characteristics of an ICU microsystem (performance obstacles and facilitators)—such as a poor 

physical work environment, supplies not well stocked, many family needs, and ineffective 

communication among multidisciplinary team members—significantly affect situation-level 

workload.22 For example, sometimes several members of the same family may call a nurse 

separately and ask very similar questions regarding the same patient’s condition. Answering all 

these different calls and repeating the same information about the patient’s status to different 

members of the family is a performance obstacle that significantly increases the (situation-level) 

workload of nurse. 

It is important to note that the impact of this performance obstacle on nursing workload 

would not be apparent if we used a unit-level or patient-level workload measure. Compared to 

workload at the job level, situation-level workload is temporally bound: it explains the impact of 

a specific performance obstacle or facilitator on nursing workload over a well-defined and 

relatively short period of time (e.g., 12-hour shift), rather than using the overall experience of the 

nurse in a given microsystem. Situation-level workload is multidimensional, that is, different 

types of performance obstacles and facilitators affect different types of workload. Whereas the 

distance between the patients’ rooms assigned to a nurse affects physical workload, the condition 

of the work environment (noisy versus quiet, hectic versus calm) affects the overall effort spent 

by the nurse to perform her job.23 No prior study investigated the impact of the microsystem 

characteristics on situation-level nursing workload.19 In summary, by studying workload at the 

situation level, researchers can identify the characteristics of a microsystem that affects 

workload. This information is vital for reducing nursing workload by redesigning the 

microsystem. In the last section of this chapter, a human factors engineering approach based on 

the situation-level workload is described. 

Research Evidence 

Impact of Nursing Workload on Patients 

A heavy nursing workload seems to be related to suboptimal patient care10, 24 and may lead to 

reduced patient satisfaction.25 A 2004 report by the Agency for Healthcare Research and Quality 

(AHRQ) describes several AHRQ-funded studies on the relationship between hospital nurse 

staffing and quality of care (e.g., urinary tract infection, hospital-acquired pneumonia) and 

patient safety outcomes (e.g., failure to rescue).26

Much of the research investigating the impact of nursing workload on patient safety focused 

on linking nursing staffing levels with patient outcomes. There is strong evidence in the literature 

that nurse staffing levels significantly affect several nursing-sensitive patient outcomes.13, 26, 27 

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

Several studies found a significant relation between lower nurse staffing levels and higher 

rates of pneumonia.28-30 For example, a multisite study in California found that an increase of 1 

hour worked by registered nurses (RNs) per patient day correlated with an 8.9 percent decrease 

in the odds of pneumonia among surgical patients.28 Another study found a significant 

relationship between full-time-equivalent RNs per adjusted inpatient day and rate of pneumonia: 

the rate of pneumonia was higher with fewer nurses.31 However, other studies have not 

confirmed these findings;31, 32 for example, the evidence regarding the impact of nurse staffing 

levels on pneumonia is conflicting. As workload is affected by more than just staffing levels, a 

deeper understanding of nursing workload is required to better assess the impact of workload on 

patient outcomes. Later, a human factors engineering approach to nursing workload that can 

provide this deeper understanding of nursing workload and its causes will be described, allowing 

for the development and implementation of solutions aimed at reducing or dealing with 

workload. 

Nursing staffing levels have been shown to have a significant impact on nosocomial 

infections. For example, Needleman and colleagues13 found that among medical patients, a 

higher number of hours of care per day provided by RNs was related to lower urinary tract 

infection rates. A retrospective cohort study in a neonatal ICU revealed that the incidence of E 

cloacae infection in the unit was significantly higher when there was understaffing of nurses.33 A 

prospective study in a pediatric cardiac ICU found a significant relation between the monthly 

nosocomial infection rate in the unit and the nursing hours per patient day ratio: there were more 

nosocomial infections when the number of nursing hours per patient day was lower.34 

Although not as strong, some evidence exists regarding the impact of nurse staffing levels on 

failure to rescue (death within 30 days among patients who had complications) and mortality. A 

study using administrative data from 799 hospitals in 11 States revealed that a higher number of 

hours of RN care per day was associated with lower failure to rescue rates.13 In a study of 168 

nonfederal adult general hospitals in Pennsylvania, Aiken and colleagues10 found that each 

additional patient per nurse was associated with a 7 percent increase in the likelihood of 

mortality within 30 days of admission and in the likelihood of failure to rescue. An earlier study 

found that hospitals that had more RNs per admission had lower mortality rates.35

There were four studies that found a relationship between nurse staffing and patient 

outcomes. One study found that having a nurse-patient ratio of less than 1:2 during evening shifts 

was associated with a 20 percent increase in length of stay in patients who had abdominal aortic 

surgery in Maryland hospitals between 1994 and 1996.36 Researchers conducted studies in 1992 

and 1994 using hospital cost reports and discharge data in New York and California, finding that 

more nursing work hours were associated with reduced length of stay.37 Additionally, a critical 

incident study of Australian ICUs revealed that insufficient nursing staff was linked to drug 

administration or documentation problems, inadequate patient supervision, incorrect ventilator or 

equipment setup, and self-extubation.38

A majority of the studies on nursing workload and patient safety used nurse-patient ratio as 

the measure of nursing workload. According to research on workload in human factors 

engineering (see section above), it is well known that workload is a complex construct, more 

complex than the measure of nurse-patient ratio.11 It is unlikely that the multidimensional, 

multifaceted structure of workload can be captured by one unique, representative measure. 

Therefore, the belief is that researchers who use the nurse-patient ratio as a measure of workload 

offer a limited contribution to understanding the impact of nursing workload and designing 

solutions for reducing or mitigating nursing workload. One reason for the extensive use of the 

4 
Workload for Nurses

nurse-patient ratio may be that this measure is easy to use and is readily available in existing 

databases. But tools used by human factors researchers can comprehensively assess workload, 

facilitate the identification of the sources of excessive workload, and provide direction for 

corrective interventions.11

How Does Nursing Workload Impact Patient Safety? 

According to the Systems Engineering Initiative for Patient Safety (SEIPS) model of work 

system and patient safety,39, 40 structural/organizational characteristics of health care work 

systems, such as nursing workload, can affect quality of care and patient safety. In this section, a 

description of how nursing workload can affect patient safety will be offered (see Table 1). The 

first five mechanisms describe the impact of a heavy workload experienced by one nurse on that 

particular nurse. The last mechanism describes the systemic and organizational impact of a heavy 

workload experienced by a nurse’s coworkers and team members. 

Table 1: Relationship Between Nursing Workload and Patient Safety 

Mechanisms Description Examples 

Time Nurses who have a heavy workload may 

not have sufficient time to perform tasks 

safely, apply safe practices, or monitor 

patients, and may reduce their 

communication with physicians and other 

providers. 

No or little time to double-check 

medications 

Motivation Nurses who have a heavy workload may be 

dissatisfied with their job, thus affecting their 

motivation for high-quality performance. 

No or little motivation and commitment 

to high levels of performance High 

workload creating frustration and 

contributing to the development of 

negative attitude toward one’s job.

Stress and burnout Nurses who have a heavy workload may 

experience stress and burnout, which can 

have a negative impact on their 

performance. 

Reduced physical and cognitive 

resources available for nurses to 

perform adequately 

Errors in decisionmaking 

(attention) 

High cognitive workload (one dimension of 

nursing workload) can contribute to errors, 

such as slips and lapses or mistakes. 

Forgetting to administer medications 

Violations or work-arounds High workload conditions may make it more 

difficult for nurses to follow rules and 

guidelines, thus compromising the quality 

and safety of patient care. 

Inadequate hand washing 

Systemic/organizational 

impact 

The heavy workload of a nurse, nurse 

manager, or another provider could affect 

the safety of care provided by another 

nurse. 

A charge nurse may not be available to 

help other nurses with their patients 

when needed. 

Nursing workload and lack of time. Nursing workload definitely affects the time that a 

nurse can allot to various tasks. Under a heavy workload, nurses may not have sufficient time to 

perform tasks that can have a direct effect on patient safety. A heavy nursing workload can 

influence the care provider’s decision to perform various procedures.41 A heavy workload may 

also reduce the time spent by nurses collaborating and communicating with physicians, therefore 

affecting the quality of nurse-physician collaboration.42 A heavy workload can lead to poor 

nurse-patient communication.43, 44

5
Patient Safety and Quality: An Evidence-Based Handbook for Nurses

Nursing workload and deteriorated motivation. Several studies have shown the 

relationship between nurses’ working conditions, such as high workload, and job 

dissatisfaction.10, 45, 46 Job dissatisfaction of nurses can lead to low morale, absenteeism, 

turnover, and poor job performance, and potentially threaten patient care quality and 

organizational effectiveness.47 Researchers have found positive associations between job 

satisfaction and job performance,48 and patient satisfaction and quality of care.49

Impact of workload on nursing stress and burnout. High workload is a key job stressor of 

nurses in a variety of care settings, such as ICUs.15, 16, 50 A heavy nursing workload can lead to 

distress (e.g., cynicism, anger, and emotional exhaustion)51 and burnout.10 Nurses experiencing 

stress and burnout may not be able to perform efficiently and effectively because their physical 

and cognitive resources may be reduced; this suboptimal performance may affect patient care 

and its safety. 

Nursing workload and errors. Workload can be a factor contributing to errors.52, 53 Errors 

have been classified as (1) slips and lapses or execution errors, and (2) mistakes or knowledge 

errors.52 High workload in the form of time pressure may reduce the attention devoted by a nurse 

to safety-critical tasks, thus creating conditions for errors and unsafe patient care. 

Nursing workload and violations or work-arounds. Violations are defined as deliberate 

deviations from those practices (i.e., written rules, policies, instructions, or procedures) believed 

necessary to maintain safe or secure operations.54 The literature on violations emphasizes the role 

of the social and organizational context, where behavior is governed by operating procedures, 

codes of practice, rules, and regulations.54, 55 This approach emphasizes factors in the work 

system that can contribute to violations. The health care field has begun to explore caregivers’ 

violations of protocols.56 A survey describing medical practice was administered to 315 nurses, 

doctors, and midwives and 350 members of the general public in the United Kingdom. The study 

examined two factors manipulated within nine scenarios of surgery, anesthetics, and obstetrics. 

The first factor, behavior, was described as an improvisation (no rule available), a violation of 

clinical protocol, or compliance with a clinical protocol. The second factor, patient outcome, was 

described as good, bad, or poor. Samples of health care providers and the general public were 

asked to evaluate the nine scenarios with regard to the inappropriateness of the behavior, the 

likelihood that they would take further action (i.e., reporting by health care provider and 

complaining by the public), and responsibility for the outcome (e.g., the health care professional, 

the patient, the protocol itself, the hospital). Results showed that violations of protocols and bad 

outcomes were judged most harshly. Whether outcomes were good or bad, violations were 

evaluated more negatively. The authors of the study warned against overreliance on procedures 

(or protocols) as a form of organizational defense against accidents or claims. Procedures may 

stifle innovation and make people less able to function in novel situations. 

Alper and colleagues57 conducted a survey of 120 nurses (59 percent response rate) in three 

units of a pediatric hospitals to assess self-reports of violations in the medication administration 

process. Between 8 percent and 30 percent of the nurses reported violations in routine situations, 

and between 32 percent and 53 percent of the nurses reported violations in emergency situations. 

The most frequent violations or work-arounds occurred in matching the medication to the 

medication administration record and checking the patient’s identification. 

Further research is needed to understand the work system factors that lead to violations. 

Violations occur more frequently when nurses are under time pressure or high workload because 

of emergency situations. Under high workload, nurses may not have time to follow rules and 

6 
Workload for Nurses

guidelines for safe care, especially if following the rules and guidelines necessitate additional 

time, such as hand washing. 

Systemic, organizational impact of nursing workload. This final mechanism of the 

relationship between nursing workload and patient safety is based on the systemic, 

organizational impact of nursing workload: a heavy workload experienced by a nurse not only 

affects this nurse, but can also affect other nurses and health care providers in the nurse’s work 

system. Understaffing may reduce time nurses have to help other nurses. This lack of time may 

also result in inadequate training or supervision of new nurses. 

Practice and Research Implications 

We propose a human factors engineering approach to nursing workload and patient safety, 

which is based on the SEIPS model of work system and patient safety.58, 59 This approach is 

based on the key principle of human factors engineering, i.e., work system design.60, 61

According to the work system model,several elements of the work system can affect nurses and 

their performance, safety, and well-being.58 These work system elements are causes or factors 

contributing to nursing workload. The first step of the proposed approach is therefore to 

understand how the work system of nurses can contribute to their workload. Human factors 

engineers have developed and used various methods to assess each element of the work system 

model and the interaction between the elements,62 such as observations of the work situation;62, 63

direct measurement of the work environment and workstation; and interviews, focus groups, and 

survey of workers.40, 64 Once the human factors engineers have identified the elements and 

characteristics of the nurses’ work system that contribute to workload, they can redesign the 

work system to reduce the workload. 

In a previous study,23 the causes of situational workload experienced by nurses in 17 ICUs in 

Wisconsin were identified, demonstrating that there were differences in the factors that lead to a 

heavy nursing workload in different ICUs. For example, compared to their colleagues in other 

participating ICUs, a higher number of nurses of a 24-bed medical surgical ICU reported the 

following factors that led to high workload: difficulty finding a place to sit down and do 

paperwork, distance between patients’ rooms, poor condition of the equipment, spending a lot of 

time searching for patients’ charts, and a crowded and disorganized work environment. Since 

this ICU was larger than the other ICUs in the study and many specialties were involved in the 

care of patients in this ICU, it was not surprising to see such work system factors as a crowded 

and disorganized work environment, and spending a lot of time searching for patients’ charts 

(e.g., different specialties searching for the chart during the day). 

Once the work system factors contributing to nursing workload have been identified, 

interventions aimed at reducing or mitigating the workload can be designed. The work system 

redesign interventions should follow the two basic principles of the Balance Theory of Carayon 

and Smith: (1) eliminating the source of the excessive workload, or (2) compensating or 

balancing out the workload.60, 61 According to the Balance Theory, redesigning the work system 

should aim at eliminating the negative aspects of work; however, this is not always feasible or 

practical. The Balance Theory, therefore, proposes an alternative approach aimed at 

compensating for or balancing out the negative aspects of work. For instance, “making available 

to nurses resources and social support to assist them in accomplishing their duties”50, 51 can be 

conceptualized as a compensating mechanism: different types of support (e.g., informational 

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

support, practical support, affective support) can be provided to help nurses deal with negative 

aspects of their work, such as workload. 

Another key concept of the human factors engineering approach to nursing workload is the 

work system: any change in one element of the work system can affect other elements of the 

work system in negative and/or positive ways.60, 61 For instance, work hour limits for physicians 

have affected nurse schedules. Nurses are often required to work increased overtime to 

compensate for reduced physician hours.65 This is an example of how changing one element in 

the work system of physicians can negatively affect the work system of nurses. Table 2 

summarizes the research implications of the proposed human factors engineering approach to 

nursing workload and patient safety. 

Table 2: Research Implications on Nursing Workload and Patient Safety 

Research Implications Objectives 

Measurement of situational workload Test and evaluate various methods for measuring nursing 

workload at the situational level. 

Identification of work system factors that contribute 

to situational workload 

Identify the work system factors that contribute to nurses’ 

situational workload under various conditions and in various 

care settings. 

Evaluation of the impact of situational workload on 

outcomes 

Evaluate the impact of situational workload on various 

outcomes, such as nurses’ job satisfaction and stress, 

nurses’ perceptions of quality and safety of care, and patient 

outcomes. Conduct this research in various care settings and 

organizational settings. 

Development of strategies for reducing situational 

workload 

Develop, implement, and evaluate interventions for reducing 

situational workload and its negative impact on nurses and 

patients. 

Evaluation of barriers to improving nurses’ work 

system and reducing situational workload 

Identify the organizational and structural barriers to effective 

changes in nurses’ work system and the challenges in 

reducing situational workload. 

Conclusion 

Nursing workload is affected by staffing levels and the patients’ conditions, but also by the 

design of the nurses’ work system. In this chapter, a description of different levels of workload, 

including situational workload, was offered, and a proposal for a human factors engineering 

approach aimed at reducing workload or at mitigating or balancing the impact of workload on 

nurses and patient care was suggested. 

Author Affiliation 

Pascale Carayon, Ph.D., Department of Industrial and Systems Engineering, Center for 

Quality and Productivity Improvement, University of Wisconsin–Madison. E-mail: 

carayon@engr.wisc.edu.

Ayse P. Gurses, Assistant Professor, Division of Health Policy and Management, School of 

Public Health, University of Minnesota–Twin Cities. Email: gurse001@umn.edu. 

8 
Workload for Nurses

Acknowledgments 

This chapter is partially based on a project funded by a Health Services Research Dissertation 

Grant (# R03 HS14517-01) from the Agency for Healthcare Research and Quality. 

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11
Evidence Table. Nurse workload and patient safety

Source Safety Issue Related to Clinical Practice Design Type Study Design & Study Outcome Measure(s) Study Setting & Study Population Key Finding(s) Aiken 200210 Hospital nurse staffing Cross-sectional study Risk-adjusted patient mortality, failure to rescue, job dissatisfaction, job-related burnout Linked data from 10,184 nurses surveyed, 232,342 surgical patients discharged from the hospital between 04/01/1998 and 11/30/1999, and administrative data from 168 hospitals in Pennsylvania In hospitals with 

ratios, patients day mortality anrates, and nursereport burnout a

Anderson & Maloney 199825 Nurse workload and patient satisfaction Cross-sectional study Patient satisfaction Survey data from 188 patients in a 250-bed Army medical treatment facility Patient satisfac

correlated with and positively cnumber of nursand the number available. Archibald 199734 Nurse staffing levels and patient census in ICU Cross-sectional study Rate of nosocomial infections per 1000 patient days One pediatric cardiac intensive care unit; 782 admissions during one year Higher patient chigher rates of nThere was an inbetween the moinfection rates aratio. Beckmann 

199838 Nursing staffing issues in incidents 

reported by ICU staff 

Noncomparative study 

Incidents associated with nursing staff shortage reported to the Australian Incident Monitoring Study-ICU (AIMS-ICU) project 

89 nursing staff shortage incidents and 373 incidents involving nursing staff shortage contributing factors 

Incidents involvshortage contribproblems in uniand patient man

12
13

Source 

Safety Issue Related to Clinical Practice 

Design Type 

Study Design & Study Outcome Measure(s) 

Study Setting & Study Population Key Finding(s) 

Keijsers 199524 Burnout (emotional exhaustion and 

depersonalization) 

Cross-sectional study 

Standardized mortality ratio for each of the 20 participating ICUs; perceived personal performance; perceived ICU performance 

576 nurses from 20 ICUs High burnout of 

to poor perceivepoor perceived Nurses in well-pmeasured by thratio) reported hnurses in poor-p

Lichtig 199937 Nurse staffing Cross-sectional study Adverse patient 

outcomes (pressure ulcers, pneumonia, UTIs, postoperative infections), length of stay 

Hospital cost reports and patient discharge data from hospitals in the States of California and New York 

Higher nurse stproportion of RNlength of stay. Loutcomes were proportion of RN

Manheim 199235 Regional variation in hospital mortality Cross-sectional study Severity- adjusted 

Medicare hospital mortality rate 

3,796 hospitals in nine US Census regions 

The percentage admission was mortality rates. 

Needleman 200213 Hours of nursing care per patient Cross-sectional study Rates of urinary tract 

infections, rates of failureto-rescue, inhospital death, rate of adverse outcomes 

Administrative data from 1997 for 799 hospitals in 11 States 

A higher proporcare was relatecare outcomes, urinary tract infepatients and lowshock or cardiarescue” among was no associanursing care pehospital death radverse outcom
14

Source Safety Issue Related to Clinical Practice Design Type Study Design & Study Outcome Measure(s) Study Setting & Study Population Key Finding(s) Pronovost 199936 Organizational characteristics of ICUs Observational study with patient data collected retrospectively and ICU data collected prospectively In-hospital mortality and hospital and ICU length of stay All Maryland hospitals that performed abdominal aortic surgery from 1994 to 1996 Having an ICU 

less than 1:2 waincreased resou