The Impact of the New York Nurse Practitioner Modernization Act on the Employment of Nurse Practitioners in Primary Care.

Expanding scope of practice (SOP) for nurse practitioners (NPs) may increase NP employment in primary care practices which can help meet the growing demand in primary care. We examined the impact of enacting less restrictive NP practice restrictions-NP Modernization Act-in New York State (NYS) on the overall employment of primary care NPs and specifically in underserved areas. We used longitudinal data from the SK&A outpatient database (2012-2018) to identify primary care practices in NYS and in the comparison states (Pennsylvania [PA] and New Jersey [NJ]). Using a difference-in-differences design with an event study specification, we compared changes in (1) the presence and (2) total counts of NPs in primary care practices in NYS and neighboring comparison states (ie, PA and NJ) before and after the policy change. The NP Modernization Act was associated with a 1.3 percentage point lower probability of a practice employing at least one NP on average across each of the 3 post-periods (95% CI: -.024, -.002). NP Modernization Act was associated with 0.065 fewer NPs on average across the post-period (95% CI: -.119, -.011). Results were similar in underserved areas. NP employment in primary care practices in NYS was lower after the NP Modernization Act than would have been expected based counterfactual of comparison states. The negative relationship may be explained by gains in provider efficiency which leads to reduced NP hiring in primary care. More research is needed to understand the relationship between SOP regulations, NP supply, and access to care.

Relationship between rural hospital closures and the supply of nurse practitioners and certified registered nurse anesthetists.

BACKGROUND: Reductions in primary care and specialist physicians follow rural hospital closures. As the supply of physicians declines, rural healthcare systems increasingly rely on nurse practitioners (NPs) and certified registered nurse anesthetists (CRNAs) to deliver care. PURPOSE: We sought to examine the extent to which rural hospital closures are associated with changes in the NP and CRNA workforce. METHOD: Using Area Health Resources Files (AHRF) data from 2010-2017, we used an event-study design to estimate the relationship between rural hospital closures and changes in the supply of NPs and CRNAs. FINDINGS: Among 1,544 rural counties, we observed 151 hospital closures. After controlling for local market characteristics, we did not find a significant relationship between hospital closure and the supply of NPs and CRNAs. DISCUSSION: We do not find evidence that NPs and CRNAs respond to rural hospital closures by leaving the healthcare market.

Differences in the number of services provided by nurse practitioners and physicians during primary care visits.

BACKGROUND: Due to differential training, nurse practitioners (NPs) and physicians may provide different quantities of services to patients. PURPOSE: To assess differences in the number of laboratory, imagining, and procedural services provided by primary care NPs and physicians. METHODS: Secondary analysis of 2012-2016 National Ambulatory Medical Care Survey (NAMCS), containing 308 NP-only and 73,099 physician-only patient visits, using multivariable regression and propensity score techniques. FINDINGS: On average, primary care visits with NPs versus physicians were associated with 0.521 fewer laboratory (95% CI -0.849, -0.192), and 0.078 fewer imaging services (95% CI -0.103,-0.052). Visits for routine and preventive care with NPs versus physicians were associated with 1.345 fewer laboratory (95% CI -2.037,-0.654), and 0.086 fewer imaging services (95% CI -0.118,-0.054) on average. Primary care visits for new problems with NPs versus physicians were associated with 0.051 fewer imaging services (95% CI -0.094,-0.007) on average. DISCUSSION: NPs provide fewer laboratory and imaging services than physicians during primary care visits.

The Surgical and Anesthesia Workforce and Provision of Surgical Services in Rural Communities: A Mixed-Methods Examination.

PURPOSE: Rural-urban disparities in the surgical and anesthesia workforce exist. This mixed-methods study describes the distribution of the surgical and anesthesia workforce and qualitatively explores how such workforce and other factors influence rural hospitals' provision of surgical services. METHODS: We calculated provider counts by county from the Area Health Resource File. Using American Hospital Association survey data, we sampled rural hospitals, stratified by critical access status and state policies. We conducted qualitative semistructured interviews with administrators at 16 hospitals and performed directed content analysis of factors influencing surgical services provision at rural hospitals. FINDINGS: Within rural counties, 55.1% of counties had no surgeon, 81.2% had no anesthesiologist, and 58.1% had no Certified Registered Nurse Anesthetist (CRNA). Administrators reported that rural hospitals struggled to provide many surgical services given lack of subspecialty surgeons and adequate postsurgical care. Rural hospitals likely struggle to generate volumes necessary to support safe and profitable subspecialty surgery programs. Anesthesia services were not reported as a current limitation given that CRNAs in particular had strong, diverse skills sets and many hospitals allowed high CRNA autonomy. However, meeting anesthesia needs for emergency surgeries and 24-hour obstetrics posed significant challenges. CONCLUSIONS: While rural hospitals reported meeting community needs for elective and noncomplex surgeries, rural hospitals continued to face significant challenges providing subspecialty surgeries, emergency surgeries, and 24-hour obstetrical services.

Nurse Practitioner Scope of Practice Regulations and Nurse Practitioner Supply.

Adopting full scope of practice (SOP) for nurse practitioners (NPs) is associated with improved access to care. One possible mechanism for these improvements is increased NP supply. Using county-level data, we fit cross-sectional and panel regression models to estimate the association between adopting full NP SOP and NP supply in general, and in rural and health professional shortage area-designated counties in particular. In cross-sectional analyses, we estimated positive associations between NP SOP and NP supply, though these relationships were only statistically significant when analyzing health professional shortage areas. In the panel regression models with county fixed effects, the estimated effects were attenuated toward zero and sometimes switched signs. Our findings suggest that improvements in access to care following adoption of full SOP may not be driven by increased NP supply but rather by increased capacity of NPs and physicians to provide care.

Practice Expenses Associated with Comprehensive Primary Care Capabilities.

Through the Comprehensive Primary Care (CPC) and Comprehensive Primary Care Plus (CPC+) programs, the Centers for Medicare & Medicaid Services (CMS) has encouraged primary care practices to invest in "comprehensive primary care" capabilities. Empirical evidence suggests these capabilities are under-reimbursed or not reimbursed under prevailing fee-for-service payment models. To help CMS design alternative payment models (APMs) that reimburse the costs of these capabilities, the authors developed a method for estimating related practice expenses. Fifty practices, sampled for diversity across CPC+ participation status, geographic region, rural status, size, and parent-organization affiliation, completed the study. Researchers developed a mixed-methods strategy, beginning with interviews of practice leaders to identify their capabilities and the types of costs incurred. This was followed by researcher-assisted completion of a workbook tailored to each practice, which gathered related labor and nonlabor costs. In a final interview, practice leaders reviewed cost estimates and made any needed corrections before approval. A main goal was to address a persistent question faced by CMS: When practices reported widely divergent costs for a given capability, was that divergence due to practices having different prices for the same capability or from their having substantially different capabilities? The cost estimation method developed in this project collected detailed data on practice capabilities and their costs. However, the small sample did not allow quantitative estimation of the contributions of service level and pricing to the variation in overall costs. This cost estimation method, deployed on a larger scale, could generate robust data to inform new payment models aimed at incentivizing and sustaining comprehensive primary care.

Provider Interventions to Increase Uptake of Evidence-Based Treatment for Depression: A Systematic Review.

The objective of this systematic review was to synthesize the effectiveness of health care provider interventions that aim to increase the uptake of evidence-based treatment of depression in routine clinical practice. This study summarizes results of comprehensive searches in the quality improvement, implementation science, and behavior change literature. Studies evaluated diverse provider interventions such as sending out depression guidelines to providers, education and training such as academic detailing, and combinations of education with other components such as targeting implementation barriers. A detailed critical appraisal process assessed risk of bias and study quality. The body of evidence was graded using established evidence synthesis criteria. Twenty-two randomized controlled trials promoting uptake of clinical practice guidelines and guideline-concordant practices met inclusion criteria. Results were heterogeneous and analyses comparing interventions with usual clinical practice did not indicate a statistically significant difference in guideline adherence across studies. There was some evidence that interventions improved individual outcomes such as medication prescribing and indirect comparisons indicated that more complex interventions may be associated with more favorable outcomes. However, we did not identify types of interventions that were consistently associated with improvements across indicators of guideline adherence and across studies. Due to the small number of studies reporting team interventions or approaches tested in specialty care we did not identify robust evidence that effects vary by provider group or setting. Low quality of evidence and lack of replication of specific intervention strategies limited conclusions that can be drawn from the existing research.

Work Performance Among Informal Caregivers: A Review of the Literature.

Objectives: To examine the association between informal caregiving and caregiver work performance. Method: A systematized review of the literature. Results: We found that caregiving has an adverse impact on work performance: caregivers experience substantial work disruptions and negative work performance outcomes, and these findings were consistent across measures. Our synthesis suggests that caregivers miss a significant amount of work and have reductions in productivity due to their caregiving responsibilities. However, significant methodological limitations with the reviewed studies make systematic interpretations and causal determinations challenging. Discussion: Examining the effect of caregiving on work performance is critical to better understand the full impact of caregiving, especially as demand for caregivers increases as the population ages. This comprehensive review suggests that caregiving has a significant negative impact on work performance, although methodological challenges remain in this area of science. These findings should inform both public policy development and workplace benefits design.

When Rural Hospitals Close, The Physician Workforce Goes.

Rates of rural hospital closures have been increasing over the past decade. Closures will almost certainly restrict rural residents' access to important inpatient services, and they could also be related in important ways to the supply of physicians in the local health care system. We used data from the Area Health Resources Files for the period 1997-2016 to examine the relationship between rural hospital closures and the supply of physicians across different specialties in the years leading up to and after a closure. We observed significant annual reductions of up to 8.3 percent in the supply of general surgeons in the years leading up to a closure. We also found that rural hospital closures were associated with immediate and persistent decreases in the supply of surgical specialists and long-term decreases in the supply of physicians across multiple specialties-including an average annual 8.2 percent decrease in the supply of primary care physicians in the six years after a closure and beyond. This dynamic relationship could lead to reduced access to care for rural residents. Future policy efforts must focus on supporting and maintaining health care delivery models that do not depend on hospitals.

Estimating the Costs of Implementing Comprehensive Primary Care: A Narrative Review.

The performance of the any health-care system relies on a high-functioning primary care system. Increasing primary care practices' adoption of "comprehensive primary care" capabilities might yield meaningful improvements in the quality and efficiency of primary care. However, many comprehensive primary care capabilities, such as care management and coordination, are not compensated via traditional fee-for-service payment. To calculate new payments for these capabilities, policymakers would need estimates of the costs that practices incur when adopting, maintaining, and using the capabilities. We performed a narrative review of the existing literature on the costs of adopting and implementing comprehensive primary care capabilities. These studies have found that practices incur significant costs when adopting and implementing comprehensive primary care capabilities. However, the studies had significant limitations that prevent extensive use of their estimates for payment policy. Particularly, the strongest studies focused on a small numbers of practices in specific geographic areas and the concepts and methods used to assess costs varied greatly across the studies. Furthermore, none of the studies in our review attempted to estimate differences in costs across practices with patients at varying levels of complexity and illness burden which is important for risk-adjusting payments to practices. Therefore, due to the heterogeneous designs and limited generalizability of published studies highlight the need for additional research, especially if payers wish to link their financial support for comprehensive primary care capabilities to the costs of these capabilities for primary care practices.

Elusive search for effective provider interventions: a systematic review of provider interventions to increase adherence to evidence-based treatment for depression.

BACKGROUND: Depression is a common mental health disorder for which clinical practice guidelines have been developed. Prior systematic reviews have identified complex organizational interventions, such as collaborative care, as effective for guideline implementation; yet, many healthcare delivery organizations are interested in less resource-intensive methods to increase provider adherence to guidelines and guideline-concordant practices. The objective of this systematic review was to assess the effectiveness of healthcare provider interventions that aim to increase adherence to evidence-based treatment of depression in routine clinical practice. METHODS: We searched five databases through August 2017 using a comprehensive search strategy to identify English-language randomized controlled trials (RCTs) in the quality improvement, implementation science, and behavior change literature that evaluated outpatient provider interventions, in the absence of practice redesign efforts, to increase adherence to treatment guidelines or guideline-concordant practices for depression. We used meta-analysis to summarize odds ratios, standardized mean differences, and incidence rate ratios, and assessed quality of evidence (QoE) using the GRADE approach. RESULTS: Twenty-two RCTs promoting adherence to clinical practice guidelines or guideline-concordant practices met inclusion criteria. Studies evaluated diverse provider interventions, including distributing guidelines to providers, education/training such as academic detailing, and combinations of education with other components such as targeting implementation barriers. Results were heterogeneous and analyses comparing provider interventions with usual clinical practice did not indicate a statistically significant difference in guideline adherence across studies. There was some evidence that provider interventions improved individual outcomes such as medication prescribing and indirect comparisons indicated more complex provider interventions may be associated with more favorable outcomes. We did not identify types of provider interventions that were consistently associated with improvements across indicators of adherence and across studies. Effects on patients' health in these RCTs were inconsistent across studies and outcomes. CONCLUSIONS: Existing RCTs describe a range of provider interventions to increase adherence to depression guidelines. Low QoE and lack of replication of specific intervention strategies across studies limited conclusions that can be drawn from the existing research. Continued efforts are needed to identify successful strategies to maximize the impact of provider interventions on increasing adherence to evidence-based treatment for depression. TRIAL REGISTRATION: PROSPERO record CRD42017060460 on 3/29/17.

Estimating Associations Between Medical Home Adoption, Utilization, and Quality: A Comparison of Evaluation Approaches.

BACKGROUND: Methodological differences between evaluations of medical home adoption might complicate readers' ability to draw conclusions across studies. OBJECTIVES: To study whether associations between medical home adoption and patient care are affected by methodological choices. DESIGN, SETTING, AND SUBJECTS: Among 71 practices participating in the Pennsylvania Chronic Care Initiative (a medical home pilot), we estimated cross-sectional and longitudinal associations between 4 definitions of "medical home adoption" [National Committee on Quality Assurance (NCQA) recognition in year 3, Medical Home Index scores at baseline and 3, and within-practice changes in Medical Home Index scores between baseline and year 3] and utilization and quality. MEASUREMENTS: Six utilization and 6 quality measures. RESULTS: In cross-sectional analyses at year 3, NCQA recognition was associated with higher rates of nephropathy monitoring (7.23 percentage points; confidence interval, 0.45-14.02), breast cancer screening (7.48; 2.11-12.86), and colorectal cancer screening (8.43; 2.44-14.42). In longitudinal analyses, NCQA recognition was associated with increases in hospitalization rates (2.75 per 1000 patient-months; 0.52-4.98). In baseline cross-sectional analyses, higher Medical Home Index scores were associated with fewer ambulatory care-sensitive hospitalizations (-0.61 per 1000 patient per month; -1.11 to -0.11), all-cause emergency department visits (-6.80; -12.28 to -1.32), and ambulatory care-sensitive emergency department visits (-5.60; 10.32 to -0.88). There were no statistically significant associations between any other measure of medical home adoption and quality or utilization. CONCLUSIONS: The findings of medical home evaluations are sensitive to methodological choices. Meta-analyses, narrative reviews, and other syntheses of medical home studies should consider subdividing their findings by analytic approach.

Evaluation of Policy Options for Increasing the Availability of Primary Care Services in Rural Washington State.

The Washington State legislature has recently considered several policy options to address a perceived shortage of primary care physicians in rural Washington. These policy options include opening the new Elson S. Floyd College of Medicine at Washington State University in 2017; increasing the number of primary care residency positions in the state; expanding educational loan-repayment incentives to encourage primary care physicians to practice in rural Washington; increasing Medicaid payment rates for primary care physicians in rural Washington; and encouraging the adoption of alternative models of primary care, such as medical homes and nurse-managed health centers, that reallocate work from physicians to nurse practitioners (NPs) and physician assistants (PAs). RAND Corporation researchers projected the effects that these and other policy options could have on the state's rural primary care workforce through 2025. They project a 7-percent decrease in the number of rural primary care physicians and a 5-percent decrease in the number of urban ones. None of the policy options modeled in this study, on its own, will offset this expected decrease by relying on physicians alone. However, combinations of these strategies or partial reallocation of rural primary care services to NPs and PAs via such new practice models as medical homes and nurse-managed health centers are plausible options for preserving the overall availability of primary care services in rural Washington through 2025.

Introducing Value-Based Purchasing into TRICARE Reform.

TRICARE, the health benefits program created for beneficiaries of the U.S. Department of Defense, covers health care provided in military treatment facilities and by civilian providers. Congress is now considering how to update TRICARE, which was first developed in the 1980s drawing on managed care concepts from civilian health plans. This article places TRICARE's current managed care strategy in historical context and describes recent innovations by private insurers and Medicare intended to enhance the value---cost and quality---of the care they purchase for their members. With this movement toward value-based purchasing as background, the authors evaluate two existing proposals for reform and describe an alternative approach that blends the existing proposals.

Efficacy of mindfulness meditation for smoking cessation: A systematic review and meta-analysis.

BACKGROUND: Smokers increasingly seek alternative interventions to assist in cessation or reduction efforts. Mindfulness meditation, which facilitates detached observation and paying attention to the present moment with openness, curiosity, and acceptance, has recently been studied as a smoking cessation intervention. AIMS: This review synthesizes randomized controlled trials (RCTs) of mindfulness meditation (MM) interventions for smoking cessation. METHODS: Five electronic databases were searched from inception to October 2016 to identify English-language RCTs evaluating the efficacy and safety of MM interventions for smoking cessation, reduction, or a decrease in nicotine cravings. Two independent reviewers screened literature using predetermined eligibility criteria, abstracted study-level information, and assessed the quality of included studies. Meta-analyses used the Hartung-Knapp-Sidik-Jonkman method for random-effects models. The quality of evidence was assessed using the GRADE approach. FINDINGS: Ten RCTs of MM interventions for tobacco use met inclusion criteria. Intervention duration, intensity, and comparison conditions varied considerably. Studies used diverse comparators such as the American Lung Association's Freedom from Smoking (FFS) program, quitline counseling, interactive learning, or treatment as usual (TAU). Only one RCT was rated as good quality and reported power calculations indicating sufficient statistical power. Publication bias was detected. Overall, mindfulness meditation did not have significant effects on abstinence or cigarettes per day, relative to comparator groups. The small number of studies and heterogeneity in interventions, comparators, and outcomes precluded detecting systematic differences between adjunctive and monotherapy interventions. No serious adverse events were reported. CONCLUSIONS: MM did not differ significantly from comparator interventions in their effects on tobacco use. Low-quality evidence, variability in study design among the small number of existing studies, and publication bias suggest that additional, high-quality adequately powered RCTs should be conducted.

Association Between the Opening of Retail Clinics and Low-Acuity Emergency Department Visits.

STUDY OBJECTIVE: We assess whether the opening of retail clinics near emergency departments (ED) is associated with decreased ED utilization for low-acuity conditions. METHODS: We used data from the Healthcare Cost and Utilization Project State Emergency Department Databases for 2,053 EDs in 23 states from 2007 to 2012. We used Poisson regression models to examine the association between retail clinic penetration and the rate of ED visits for 11 low-acuity conditions. Retail clinic "penetration" was measured as the percentage of the ED catchment area that overlapped with the 10-minute drive radius of a retail clinic. Rate ratios were calculated for a 10-percentage-point increase in retail clinic penetration per quarter. During the course of a year, this represents the effect of an increase in retail clinic penetration rate from 0% to 40%, which was approximately the average penetration rate observed in 2012. RESULTS: Among all patients, retail clinic penetration was not associated with a reduced rate of low-acuity ED visits (rate ratio=0.999; 95% confidence interval=0.997 to 1.000). Among patients with private insurance, there was a slight decrease in low-acuity ED visits (rate ratio=0.997; 95% confidence interval=0.994 to 0.999). For the average ED in a given quarter, this would equal a 0.3% reduction (95% confidence interval 0.1% to 0.6%) in low-acuity ED visits among the privately insured if retail clinic penetration rate increased by 10 percentage points per quarter. CONCLUSION: With increased patient demand resulting from the expansion of health insurance coverage, retail clinics may emerge as an important care location, but to date, they have not been associated with a meaningful reduction in low-acuity ED visits.

Impact of Race/Ethnicity and Socioeconomic Status on Risk-Adjusted Hospital Readmission Rates Following Hip and Knee Arthroplasty.

BACKGROUND: Readmission rates following total hip arthroplasty (THA) and total knee arthroplasty (TKA) are increasingly used to measure hospital performance. Readmission rates that are not adjusted for race/ethnicity and socioeconomic status, patient risk factors beyond a hospital's control, may not accurately reflect a hospital's performance. In this study, we examined the extent to which risk-adjusting for race/ethnicity and socioeconomic status affected hospital performance in terms of readmission rates following THA and TKA. METHODS: We calculated 2 sets of risk-adjusted readmission rates by (1) using the Centers for Medicare & Medicaid Services standard risk-adjustment algorithm that incorporates patient age, sex, comorbidities, and hospital effects and (2) adding race/ethnicity and socioeconomic status to the model. Using data from the Healthcare Cost and Utilization Project, 2011 State Inpatient Databases, we compared the relative performances of 1,194 hospitals across the 2 methods. RESULTS: Addition of race/ethnicity and socioeconomic status to the risk-adjustment algorithm resulted in (1) little or no change in the risk-adjusted readmission rates at nearly all hospitals; (2) no change in the designation of the readmission rate as better, worse, or not different from the population mean at >99% of the hospitals; and (3) no change in the excess readmission ratio at >97% of the hospitals. CONCLUSIONS: Inclusion of race/ethnicity and socioeconomic status in the risk-adjustment algorithm led to a relative-performance change in readmission rates following THA and TKA at <3% of the hospitals. We believe that policymakers and payers should consider this result when deciding whether to include race/ethnicity and socioeconomic status in risk-adjusted THA and TKA readmission rates used for hospital accountability, payment, and public reporting. LEVEL OF EVIDENCE: Prognostic Level III. See instructions for Authors for a complete description of levels of evidence.

Acupuncture for substance use disorders: A systematic review and meta-analysis.

BACKGROUND: This systematic review aims to estimate the effects of acupuncture for adults with substance use disorders (SUDs). METHODS: We searched 7 electronic databases and bibliographies of previous studies to identify eligible randomized trials. Two independent reviewers screened citations, extracted data, and assessed risks of bias. We performed random effects meta-analyses. We assessed quality of evidence using the GRADE approach. RESULTS: We included 41 studies with 5,227 participants. No significant differences were observed between acupuncture and comparators (passive controls, sham acupuncture, treatment as usual, and active interventions) at post-intervention for relapse (SMD -0.12; 95%CI -0.46 to 0.22; 10 RCTs), frequency of substance use (SMD -0.27; -2.67 to 2.13; 2 RCTs), quantity of substance use (SMD 0.01; -0.40 to 0.43; 3 RCTs), and treatment dropout (OR 0.82; 0.63 to 1.09; 22 RCTs). We identified a significant difference in favor of acupuncture versus comparators for withdrawal/craving at post-intervention (SMD -0.57, -0.93 to -0.20; 20 RCTs), but we identified evidence of publication bias. We also identified a significant difference in favor of acupuncture versus comparators for anxiety at post-intervention (SMD -0.74, -1.15 to -0.33; 6 RCTs). Results for withdrawal/craving and anxiety symptoms were not significant at longer follow-up. Safety data (12 RCTs) suggests little risk of serious adverse events, though participants may experience slight bleeding or pain at needle insertion sites. CONCLUSIONS: Available evidence suggests no consistent differences between acupuncture and comparators for substance use. Results in favor of acupuncture for withdrawal/craving and anxiety symptoms are limited by low quality bodies of evidence.

An Examination of Hospital Nurse Staffing and Patient Experience with Care: Differences between Cross-Sectional and Longitudinal Estimates.

OBJECTIVE: To study the association between hospital nurse staffing and Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores. DATA SOURCES: State hospital financial and utilization reports, Healthcare Cost and Utilization Project State Inpatient Databases, HCAHPS survey, and American Hospital Association Annual Survey of Hospitals. STUDY DESIGN: Retrospective study using cross-sectional and longitudinal models to estimate the effect of nurse staffing levels and skill mix on seven HCAHPS measures. DATA COLLECTION/EXTRACTION METHODS: Hospital-level data measuring nurse staffing, patient experience, and hospital characteristics from 2009 to 2011 for 341 hospitals (977 hospital years) in California, Maryland, and Nevada. PRINCIPAL FINDINGS: Nurse staffing level (i.e., number of licensed practical nurses and registered nurses per 1,000 inpatient days) was significantly and positively associated with all seven HCAHPS measures in cross-sectional models and three of seven measures in longitudinal models. Nursing skill mix (i.e., percentage of all staff who are registered nurses) was significantly and negatively associated with scores on one measure in cross-sectional models and none in longitudinal models. CONCLUSIONS: After controlling for unobserved hospital characteristics, the positive influences of increased nurse staffing levels and skill mix were relatively small in size and limited to a few measures of patients' inpatient experience.