Diwas Singh Kc

Impact of Workload on Service Time and Patient Safety: An Econometric Analysis of Hospital Operations

Much of prior work in the area of service operations management has assumed service rates to be exogenous to the level of load on the system. Using operational data from patient transport services and cardiothoracic surgery---two vastly different health-care delivery services---we show that the processing speed of service workers is influenced by the system load. We find that workers accelerate the service rate as load increases. In particular, a 10% increase in load reduces length of stay by two days for cardiothoracic surgery patients, whereas a 20% increase in the load for patient transporters reduces the transport time by 30 seconds. Moreover, we show that such acceleration may not be sustainable. Long periods of increased load (overwork) have the effect of decreasing the service rate. In cardiothoracic surgery, an increase in overwork by 1% increases length of stay by six hours. Consistent with prior studies in the medical literature, we also find that overwork is associated with a reduction in quality of care in cardiothoracic surgery---an increase in overwork by 10% is associated with an increase in likelihood of mortality by 2%. We also find that load is associated with an early discharge of patients, which is in turn correlated with a small increase in mortality rate.

An Econometric Analysis of Patient Flows in the Cardiac Intensive Care Unit

This paper explores the rationing of bed capacity in a cardiac intensive care unit (ICU). We find that the length of stay for patients admitted to the ICU is influenced by the occupancy level of the ICU. In particular, a patient is likely to be discharged early when the occupancy in the ICU is high. This in turn leads to an increased likelihood of the patient having to be readmitted to the ICU at a later time. Such “bounce-backs” have implications for the overall ICU effective capacity---an early discharge immediately frees up capacity, but at the risk of a (potentially much higher) capacity requirement when the patient needs to be readmitted. We analyze these capacity implications, shedding light on the question of whether an ICU should apply an aggressive discharge strategy or if it should follow the old quality slogan and “do it right the first time.” By comparing the total capacity usage for patients who were discharged early versus those who were not, we show that an aggressive discharge policy applied to patients with lower clinical severity levels frees up capacity in the ICU. However, we find that an increased number of readmissions of patients with high clinical severity levels occur when the ICU is capacity constrained, thereby effectively reducing peak bed capacity.

The Effects of Focus on Performance: Evidence from California Hospitals

We use hospital-level discharge data from cardiac patients in California to estimate the effects of focus on operational performance. We examine focus at three distinct levels of the organization---at the firm level, at the operating unit level, and at the process flow level. We find that focus at each of these levels is associated with improved outcomes, namely, faster services at higher levels of quality, as indicated by lower lengths of stay (LOS) and reduced mortality rates. We then analyze the extent to which the superior operational outcome is driven by focused hospitals truly excelling in their operations or by focused hospitals simply “cherry-picking” easy-to-treat patients. To do this, we use an instrumental variables estimation strategy that effectively randomizes the assignment of patients to hospitals. After controlling for selective patient admissions, the previously observed benefits of firm level focus disappear; focused hospitals no longer demonstrate a statistically significant reduction in LOS or mortality rate. However, at more granular measures of focus within the hospital (e.g., operating unit level), we find that more focus leads to a shorter LOS, even after controlling for selective admission effects. This paper was accepted by Yossi Aviv, operations management.

Accumulating a Portfolio of Experience: The Effect of Focal and Related Experience on Surgeon Performance

One key driver of improvement in surgical outcomes is a surgeons prior experience. However, research notes that not all experience provides equal value for performance. How, then, should surgeons accumulate experience to improve quality outcomes? In this paper, we investigate the differential effects of focal and related (i.e., tasks similar to, but not identical to, the focal task) experience. We open up the black box of the volume-outcome relationship by going beyond just dividing experience into focal and related categories, but also considering how subtasks and context (i.e., the organization in which the work takes place) affect performance. To understand these issues, we assemble a novel data set on 71 cardiothoracic surgeons who performed more than 6,500 procedures during a period of 10 years after the introduction of a breakthrough surgical procedure. We find that, as compared to related experience, surgeon focal experience has a greater effect on surgeon performance. We also demonstrate that subtask experience has different, nonlinear performance relationships for focal and related experience. Finally, we find that focal experience is more firm specific than related experience and that nonfirm experience reduces the learning rate for both focal and related experience. We discuss implications of our findings for healthcare delivery and operations management.

Does Multitasking Improve Performance? Evidence from the Emergency Department

This paper examines the effect of multitasking on overall worker performance, as measured by processing time, throughput rate, and output quality using microlevel operational data from the field. Specifically, we study the multitasking behavior of physicians in a busy hospital emergency department (ED). By drawing on recent findings in the experimental psychology literature and the nascent work in cognitive neuroscience, we develop several hypotheses for the effect of multitasking on worker performance. We first examine how multitasking affects a physicians processing time. We find that the total time taken to discharge a given number of patients has a U-shaped response to the level of physician multitasking; that is, multitasking initially helps to reduce the time taken, but only up to a certain threshold level, after which it increases in the level of multitasking. In addition, multitasking significantly impacts quality of care. Although lower levels of multitasking are associated with improved quality...

Maintaining Beliefs in the Face of Negative News: The Moderating Role of Experience

Many models in operations management involve dynamic decision making that assumes optimal updating in response to information revelation. However, behavioral theory suggests that rather than updating their beliefs, individuals may persevere in their prior beliefs. In particular, we examine how individuals’ prior experiences and the experiences of those around them alter their belief perseverance in operational decisions after the revelation of negative news. We draw on an exogenous announcement of negative news by the Food and Drug Administration and explore how it affects interventional cardiologists deciding between two types of cardiac stents. Analyzing 147,000 choices over six years, we find that individuals do respond to negative news by using the focal production tool less often. However, we find that both individuals’ own experiences and others’ experiences alter their responses. Moreover, although individual and other experience act as substitutes before negative news, we find that this substituti...

The Impact of Hospital Advertising on Patient Demand and Health Outcomes

Does hospital advertising influence patient choice and health outcomes? We examine more than 220,000 individual patient-level visits over 24 months in Massachusetts to answer this question. We find...

Can Viagra Advertising Make More Babies

Although product advertising has been widely studied and understood in relation to the consumer’s purchase decision, advertising may also have unintended but important societal and economic consequences. In this paper, we examine a public health outcome—birth rate—associated with advertisements for erectile dysfunction (ED) drugs. Since the United States loosened regulation on direct-to-consumer television advertising for prescription drugs in 1997, ED drug makers have consistently been top spenders. By comparing advertising data with multiple birth data sets (patient-level hospital data from Massachusetts between 2001 and 2010 and micro birth certificate data from the U.S. between 2000 and 2004), we demonstrated that increased ED drug television advertising leads to a higher birth rate. According to our results, which are robust with respect to different functional forms and falsification tests, a 1% increase in ED drug advertising contributed to an increase of 0.04-0.08% of total births. Our findings suggest that beyond the customer purchase decision, advertising can have important public health outcomes, with resulting implications for policy formulation and managerial decision-making.

Are Patients Patient? The Role of Time to Appointment in Patient Flow

The current state of outpatient healthcare delivery is characterized by capacity shortages and long waits for appointments. Yet a substantial fraction of valuable doctors’ capacity is wasted due to no-shows. In this paper, we examine the effect of wait to appointment on patient flow, specifically on a patient’s decision to schedule an appointment, and subsequently arrive to it. These two decisions may be dependent, because appointments are more likely to be scheduled by patients who are more patient and are thereby more likely to show-up. To estimate the effect of wait on these two decisions, we introduce the willingness to wait (WTW), an unobservable variable that affects both bookings and arrivals for appointments. Using data from a large healthcare system, we estimate WTW with a state of the art non-parametric method. The WTW in turn allows us to estimate the effect of wait on no-shows. We observe that the effect of increased wait on the likelihood of no-show is disproportionately greater among patients with low WTW. Thus, although reducing the wait to appointment will enable a provider to capture more patient bookings, the effects of wait time on capacity utilization can be non-monotone. Contrary to the previously reported findings, our results suggest that increasing wait can sometimes be beneficial for reducing no-shows.

Benefits of Surgical Smoothing and Spare Capacity: An Econometric Analysis of Patient Flow

In this study, we examine the hospital’s ability to admit patients from its emergency department. From a medical perspective, the number of patients being admitted should depend solely on the patients’ clinical conditions. Using a large scale econometric study that includes detailed operational and clinical data on all cardiac patient encounters from a set of 128 hospitals over a period of 4 years, we show that this is not the case. In particular, we find that independent of their medical condition, many emergency patients are denied hospital admission because of a lack of inpatient beds. Our analysis suggests that having one more inpatient bed at the start of a day can increase the likelihood of an emergency room patient admission by around 3% on average. We examine two policies – active discharge, and demand smoothing – that can help hospitals improve patient access. We find that some hospitals actively discharge inpatients when beds become scarce; hospitals that follow such an active discharge protocol are, on average, able to admit more patients. We also investigate to what extent the hospital’s ability to smooth its surgical schedule impacts hospital admissions. Hospitals tend to schedule their elective patients early in the week (Mondays and Tuesdays), and discharge them by the weekend in order to minimize weekend staffing, effectively maximizing bed occupancy during the middle of the week. This “weekend effect�? artificially induces variability, and reduces effective system capacity. We find that by scheduling patients more uniformly over the week, hospitals can dramatically increase patient access, obviating the need for active dis-charges or additional capacity investment. Our analysis quantifies these effects, and can help hospitals in making effective capacity management decisions in order to improve patient flow.