Thesis Thursday: Thomas Hoe

On the third Thursday of every month, we speak to a recent graduate about their thesis and their studies. This month’s guest is Dr Thomas Hoe who has a PhD from University College London. If you would like to suggest a candidate for an upcoming Thesis Thursday, get in touch.

Essays on the economics of health care provision
Richard Blundell, Orazio Attanasio
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What data do you use in your analyses and what are your main analytical methods?

I use data from the English National Health Service (NHS). One of the great features of the NHS is the centralized data it collects, with the Hospital Episodes Statistics (HES) containing information on every public hospital visit in England.

In my thesis, I primarily use two empirical approaches. In my work on trauma and orthopaedic departments, I exploit the fact that the number of emergency trauma admissions to hospital each day is random. This randomness allows me to conduct a quasi-experiment to assess how hospitals perform when they are more or less busy.

The second approach I use, in my work on emergency departments with Jonathan Gruber and George Stoye, is based on bunching techniques that originated in the tax literature (Chetty et al, 2013; Kleven and Waseem, 2013; Saez, 2010). These techniques use interpolation to infer how discontinuities in incentive schemes affect outcomes. We apply and extend these techniques to evaluate the impact of the ‘4-hour target’ in English emergency departments.

How did you characterise and measure quality in your research?

Measuring the quality of health care outcomes is always a challenge in empirical research. Since my research primarily relies on administrative data from HES, I use the patient outcomes that can be directly constructed from this data: in-hospital mortality, and unplanned readmission.

Mortality is, of course, an outcome that is widely used, and offers an unambiguous interpretation. Readmission, on the other hand, is an outcome that has gained more acceptance as a measure of quality in recent years, particularly following the implementation of readmission penalties in the UK and the US.

What is ‘crowding’, and how can it affect the quality of care?

I use the term crowding to refer, in a fairly general sense, to how busy a hospital is. This could mean that the hospital is physically very crowded, with lots of patients in close proximity to one another, or that the number of patients outstrips the available resources.

In practice, I evaluate how crowding affects quality of care by comparing hospital performance and patient outcomes on days when hospitals deal with different levels of admissions (due to random spikes in the number of trauma admissions). I find that hospitals respond by not only cancelling some planned admissions, such as elective hip and knee replacements, but also discharge existing patients sooner. For these discharged patients, the shorter-than-otherwise stay in the hospital is associated with poorer health outcomes for patients, most notably an increase in subsequent hospital visits (unplanned readmissions).

How might incentives faced by hospitals lead to negative consequences?

One of the strongest incentives faced by public hospitals in England is to meet the government-set waiting time target for elective care. This target has been very successful at reducing wait times. In doing so, however, it may have contributed to hospitals shortening patient stays and increasing patient admissions.

My research shows that shorter hospitals stays, in turn, can lead to increases in unplanned readmissions. Setting strong wait time targets, then, is in effect trading off shorter waits (from which patients benefit) with crowding effects (which may harm patients).

Your research highlights the importance of time in the hospital production process. How does this play out?

I look at this from three dimensions, each a separate part of a patient’s journey through hospital.

The first two relate to waiting for treatment. For elective patients, this means waiting for an appointment, and previous work has shown that patients attach significant value to reductions in these wait times. I show that trauma and orthopaedic patients would be better off with further wait time reductions, even if that leads to more crowding.

Emergency patients, in contrast, wait for treatment while physically in a hospital emergency department. I show that these waiting times can be very harmful and that by shortening these wait times we can actually save lives.

The third dimension relates to how long a patient spends in hospital recovering from surgery. I show that, at least on the margin of care for trauma and orthopaedic patients, an additional day in hospital has tangible benefits in terms of reducing the likelihood of experiencing an unplanned readmission.

How could your findings be practically employed in the NHS to improve productivity?

I would highlight two areas of my research that speak directly to the policy debate about NHS productivity.

First, while the wait time targets for elective care may have led to some crowding problems and subsequently more readmissions, the net benefit of these targets to trauma and orthopaedic patients is positive. Second, the wait time target for emergency departments also appears to have benefited patients: it saved lives at a reasonably cost-effective rate.

From the perspective of patients, therefore, I would argue these policies have been relatively successful and should be maintained.

Thesis Thursday: Sarah Zheng

On the third Thursday of every month, we speak to a recent graduate about their thesis and their studies. This month’s guest is Dr Sarah Zheng who has a PhD from Boston University. If you would like to suggest a candidate for an upcoming Thesis Thursday, get in touch.

Design for performance: studies on cost and quality in U.S. health care
Z. Justin Ren, Kimberley H. Geissler, Janelle Heineke, Anita Tucker
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In the context of your PhD research, what does ‘design for performance’ mean?

“Design for performance” is a further step in managing healthcare from “pay for performance”, on which there has been decades of attention paid among practitioners and academics. Despite the long effort on “pay for performance”, the core challenge remains how to properly incentivize patients, clinicians and staff to align their behaviors with optimal, safe and cost-effective, patient-centric care. This dissertation suggests an important set of issues to consider around “design for performance” at the system and process levels.

At the system level, under what conditions does cost-sharing lead to lower total costs without reducing quality of care? Previous literature has studied contract theory and mechanism design in varied industry settings (Guajardo et al. 2012), yet very few are studied in the healthcare domain where insurance plans are offered to patients under different contract arrangements. It remains unclear whether certain contract design at such settings may lead to desired outcomes (e.g., low healthcare spending). At the process level, under what conditions and to what extent does excellent internal supply operations result in superior hospital performance? Industrial studies suggest that reliable, efficient internal supply chains that are integrated with production yield better financial and quality performance for manufacturing companies (Droge et al. 2004, Flynn et al. 2010). However, there is scant quantitative research on the impact of support departments in hospitals (Tucker et al. 2008, Fredendall et al. 2009). Studies are needed to understand the extent to which support departments impact patient care outcomes, such as adverse events.

How was quality captured in the data that you used in your analyses?

In Chapter 3 of my thesis, I studied the impact of internal service quality on one particular quality performance metric: adverse events. Specifically, it is a rate variable that is calculated by the sum of adverse events (i.e., patient falls with injury and pressure ulcers) on the unit that month divided by the number of patient days on the unit that month, which is then multiplied by 1,000. The hospital collects these data monthly. The adverse event data come from both patient record reviews and incident reports in the hospital’s safety reporting system, as is typical of this type of data (Lake and Cheung 2006). The error event data are audited internally as well as reported to CMS (Zheng et al. 2017).

This is a unique opportunity to study quality as most healthcare operations research has relied on publicly available, hospital-level quality data, such as patient mortality (e.g., Senot et al. 2015, KC and Terwiesch 2011)—which is a blunt measure of quality—or process of care measures (e.g., Boyer et al. 2012, Gardner et al. 2015, Senot et al. 2015), which have been criticized in the healthcare literature for their weak connection to clinical outcomes (Patterson et al. 2010).

You complemented your quantitative analysis with some qualitative interviews – was this a valuable exercise?

Yes, definitely. To understand further the role patients (and the patient-physician dyad) play in deciding the usage of imaging studies, I conducted in-depth conversations with both physicians and patients. Specifically, I interviewed three physicians (i.e., hospitalist, primary care provider) and one imaging technician with the average conversation time of 70 mins. I also interviewed six patients with the average conversation time of 20 mins.

I found that patients did play a role in deciding the usage of imaging studies in the way that high-deductible health plan (HDHP) patients are less likely to demand imaging studies than non-HDHP patients. However, as patients cannot distinguish low-value care from high-value care, HDHP patients avoid patient care in general. This is consistent with previous literature on patient cost-sharing and HDHPs where patients indiscriminately reduce medical care (Hibbard et al. 2008, Lohr et al. 1986). It further suggests that HDHP may be a blunt instrument, reducing all diagnostic imaging, rather than helping physicians and patients choose high-value imaging.

Did any of your findings about high-deductible health plans stand out as different from previous studies?

I wouldn’t say different but more like complementary. Previous studies found HDHPs have different impacts depending on the site and type of care (Haviland et al. 2015, Wharam et al. 2013, Bundorf 2012, Nair et al. 2009, Waters et al. 2011, Hibbard et al. 2008, Busch et al. 2006, Rowe et al. 2008, Parente et al. 2004). By explicitly testing associations between HDHP enrollment and diagnostic imaging, we provide a more complete picture for policymakers in making guidelines related to HDHP plans. Our results suggest that increases in HDHP enrollment may contribute to a slow in the growth of diagnostic imaging utilization. However, increased cost-sharing may not allow patients to differentiate between high-value and low-value utilization, and better patient awareness and education should be a crucial part of any reductions in diagnostic imaging utilization (Zheng et al. 2016).

‘Internal service quality’ is a term that doesn’t often appear in health economics journals – should researchers be dedicating more attention to this?

Yes. In our study we find improved internal service quality to be a particularly novel driver of reduced adverse events because it is not obvious a priori that support departments—most of which are not clinical in nature—could have a significant impact on clinical outcomes. In particular, we find that improving the overall average internal service quality received by a nursing unit by 0.1 on a 5-point scale is associated with a 38% reduction in adverse events per nursing unit, which has roughly the same benefit for reducing adverse events as increasing staffing on that unit by nearly one full-time equivalent nurse. In the hospital that we study, the average salary of a support service technician is lower than the average salary of a nurse. Thus, hospitals might be able to improve quality of care at a lower cost by increasing support staff to relieve the burden on nurses (Zheng et al. 2017). More studies are needed in this area to explore further internal service quality as a viable and cost-effective means to improve clinical performance.

Thesis Thursday: Francesco Longo

On the third Thursday of every month, we speak to a recent graduate about their thesis and their studies. This month’s guest is Dr Francesco Longo who has a PhD from the University of York. If you would like to suggest a candidate for an upcoming Thesis Thursday, get in touch.

Essays on hospital performance in England
Luigi Siciliani
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What do you mean by ‘hospital performance’, and how is it measured?

The concept of performance in the healthcare sector covers a number of dimensions including responsiveness, affordability, accessibility, quality, and efficiency. A PhD does not normally provide enough time to investigate all these aspects and, hence, my thesis mostly focuses on quality and efficiency in the hospital sector. The concept of quality or efficiency of a hospital is also surprisingly broad and, as a consequence, perfect quality and efficiency measures do not exist. For example, mortality and readmissions are good clinical quality measures but the majority of hospital patients do not die and are not readmitted. How well does the hospital treat these patients? Similarly for efficiency: knowing that a hospital is more efficient because it now has lower costs is essential, but how is that hospital actually reducing costs? My thesis tries to answer also these questions by analysing various quality and efficiency indicators. For example, Chapter 3 uses quality measures such as overall and condition-specific mortality, overall readmissions, and patient-reported outcomes for hip replacement. It also uses efficiency indicators such as bed occupancy, cancelled elective operations, and cost indexes. Chapter 4 analyses additional efficiency indicators, such as admissions per bed, the proportion of day cases, and proportion of untouched meals.

You dedicated a lot of effort to comparing specialist and general hospitals. Why is this important?

The first part of my thesis focuses on specialisation, i.e. an organisational form which is supposed to generate greater efficiency, quality, and responsiveness but not necessarily lower costs. Some evidence from the US suggests that orthopaedic and surgical hospitals had 20 percent higher inpatient costs because of, for example, higher staffing levels and better quality of care. In the English NHS, specialist hospitals play an important role because they deliver high proportions of specialised services, commonly low-volume but high-cost treatments for patients with complex and rare conditions. Specialist hospitals, therefore, allow the achievement of a critical mass of clinical expertise to ensure patients receive specialised treatments that produce better health outcomes. More precisely, my thesis focuses on specialist orthopaedic hospitals which, for instance, provide 90% of bone and soft tissue sarcomas surgeries, and 50% of scoliosis treatments. It is therefore important to investigate the financial viability of specialist orthopaedic hospitals relative to general hospitals that undertake similar activities, under the current payment system. The thesis implements weighted least square regressions to compare profit margins between specialist and general hospitals. Specialist orthopaedic hospitals are found to have lower profit margins, which are explained by patient characteristics such as age and severity. This means that, under the current payment system, providers that generally attract more complex patients such as specialist orthopaedic hospitals may be financially disadvantaged.

In what way is your analysis of competition in the NHS distinct from that of previous studies?

The second part of my thesis investigates the effect of competition on quality and efficiency under two different perspectives. First, it explores whether under competitive pressures neighbouring hospitals strategically interact in quality and efficiency, i.e. whether a hospital’s quality and efficiency respond to neighbouring hospitals’ quality and efficiency. Previous studies on English hospitals analyse strategic interactions only in quality and they employ cross-sectional spatial econometric models. Instead, my thesis uses panel spatial econometric models and a cross-sectional IV model in order to make causal statements about the existence of strategic interactions among rival hospitals. Second, the thesis examines the direct effect of hospital competition on efficiency. The previous empirical literature has studied this topic by focusing on two measures of efficiency such as unit costs and length of stay measured at the aggregate level or for a specific procedure (hip and knee replacement). My thesis provides a richer analysis by examining a wider range of efficiency dimensions. It combines a difference-in-difference strategy, commonly used in the literature, with Seemingly Unrelated Regression models to estimate the effect of competition on efficiency and enhance the precision of the estimates. Moreover, the thesis tests whether the effect of competition varies for more or less efficient hospitals using an unconditional quantile regression approach.

Where should researchers turn next to help policymakers understand hospital performance?

Hospitals are complex organisations and the idea of performance within this context is multifaceted. Even when we focus on a single performance dimension such as quality or efficiency, it is difficult to identify a measure that could work as a comprehensive proxy. It is therefore important to decompose as much as possible the analysis by exploring indicators capturing complementary aspects of the performance dimension of interest. This practice is likely to generate findings that are readily interpretable by policymakers. For instance, some results from my thesis suggest that hospital competition improves efficiency by reducing admissions per bed. Such an effect is driven by a reduction in the number of beds rather than an increase in the number of admissions. In addition, competition improves efficiency by pushing hospitals to increase the proportion of day cases. These findings may help to explain why other studies in the literature find that competition decreases length of stay: hospitals may replace elective patients, who occupy hospital beds for one or more nights, with day case patients, who are instead likely to be discharged the same day of admission.