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Dive into the research topics where Gilles Reinhardt is active.

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Featured researches published by Gilles Reinhardt.


CJEM | 2003

Analysis of factors influencing length of stay in the emergency department

Philip W. Yoon; Ivan P. Steiner; Gilles Reinhardt

OBJECTIVES Length of stay (LOS) is a key measure of emergency department (ED) throughput and a marker of overcrowding. Time studies that assess key ED processes will help clarify the causes of patient care delays and prolonged LOS. The objectives of this study were to identify and quantify the principal ED patient care time intervals, and to measure the impact of important service processes (laboratory testing, imaging and consultation) on LOS for patients in different triage levels. METHODS In this retrospective review, conducted at a large urban tertiary care teaching hospital and trauma centre, investigators reviewed the records of 1047 consecutive patients treated during a continuous 7-day period in January 1999. Key data were recorded, including patient characteristics, ED process times, tests performed, consultations and overall ED LOS. Of the 1047 patient records, 153 (14.6%) were excluded from detailed analysis because of incomplete documentation. Process times were determined and stratified by triage level, using the Canadian Emergency Department Triage and Acuity Scale (CTAS). Multiple linear regression analysis was performed to determine which factors were most strongly associated with prolonged LOS. RESULTS Patients in intermediate triage Levels III and IV generally had the longest waiting times to nurse and physician assessment, and the longest ED lengths of stay. CTAS triage levels predicted laboratory and imaging utilization as well as consultation rate. The use of diagnostic imaging and laboratory tests was associated with longer LOS, varying with the specific tests ordered. Specialty consultation was also associated with prolonged LOS, and this effect was highly variable depending on the service consulted. CONCLUSIONS Triage level, investigations and consultations are important independent variables that influence ED LOS. Future research is necessary to determine how these and other factors can be incorporated into a model for predicting LOS. Improved information systems will facilitate similar ED time studies to assess key processes, lengths of stay and clinical efficiency.


Annals of Emergency Medicine | 2009

Adding more beds to the emergency department or reducing admitted patient boarding times: which has a more significant influence on emergency department congestion?

Rahul K. Khare; Emilie S. Powell; Gilles Reinhardt; Martin Lucenti

STUDY OBJECTIVE We evaluate a computer simulation model designed to assess the effect on emergency department (ED) length of stay of varying the number of ED beds or altering the interval of admitted patient departure from the ED. METHODS We created a computer simulation model (Med Model) based on institutional data and augmented by expert estimates and assumptions. We evaluated simulations of increasing the number of ED beds, increasing the admitted patient departure and increasing ED census, analyzing potential effects on overall ED length of stay. Multiple sensitivity analyses tested the robustness of the results to changes in model assumptions and institutional data. RESULTS With a constant ED departure rate at the base case and increasing ED beds, there is an increase in mean length of stay from 240 to 247 minutes (95% confidence interval [CI] 0.8 to 12.6 minutes). When keeping the number of beds constant at the base case and increasing the rate at which admitted patients depart the ED to their inpatient bed, the mean overall ED length of stay decreases from 240 to 218 minutes (95% CI 16.8 to 26.2 minutes). With a 15% increase in daily census, the trends are similar to the base case results. The sensitivity analyses reveal that despite a wide range of inputs, there are no differences from the base case. CONCLUSION Our computer simulation modeled that improving the rate at which admitted patients depart the ED produced an improvement in overall ED length of stay, whereas increasing the number of ED beds did not.


Decision Sciences | 2004

The Effect of Lead Time Uncertainty on Safety Stocks

Sunil Chopra; Gilles Reinhardt; Maqbool Dada

The pressure to reduce inventory investments in supply chains has increased as competition expands and product variety grows. Managers are looking for areas they can improve to reduce inventories without hurting the level of service provided. Two areas that managers focus on are the reduction of the replenishment lead time from suppliers and the variability of this lead time. The normal approximation of lead time demand distribution indicates that both actions reduce inventories for cycle service levels above 50%. The normal approximation also indicates that reducing lead time variability tends to have a greater impact than reducing lead times, especially when lead time variability is large. We build on the work of Eppen and Martin (1988) to show that the conclusions from the normal approximation are flawed, especially in the range of service levels where most companies operate. We show the existence of a service-level threshold greater than 50% below which reorder points increase with a decrease in lead time variability. Thus, for a firm operating just below this threshold, reducing lead times decreases reorder points, whereas reducing lead time variability increases reorder points. For firms operating at these service levels, decreasing lead time is the right lever if they want to cut inventories, not reducing lead time variability.


Journal of Emergency Medicine | 2012

The relationship between inpatient discharge timing and emergency department boarding

Emilie S. Powell; Rahul K. Khare; Arjun K. Venkatesh; Ben D. Van Roo; James G. Adams; Gilles Reinhardt

BACKGROUND Patient crowding and boarding in Emergency Departments (EDs) impair the quality of care as well as patient safety and satisfaction. Improved timing of inpatient discharges could positively affect ED boarding, and this hypothesis can be tested with computer modeling. STUDY OBJECTIVE Modeling enables analysis of the impact of inpatient discharge timing on ED boarding. Three policies were tested: a sensitivity analysis on shifting the timing of current discharge practices earlier; discharging 75% of inpatients by 12:00 noon; and discharging all inpatients between 8:00 a.m. and 4:00 p.m. METHODS A cross-sectional computer modeling analysis was conducted of inpatient admissions and discharges on weekdays in September 2007. A model of patient flow streams into and out of inpatient beds with an output of ED admitted patient boarding hours was created to analyze the three policies. RESULTS A mean of 38.8 ED patients, 22.7 surgical patients, and 19.5 intensive care unit transfers were admitted to inpatient beds, and 81.1 inpatients were discharged daily on September 2007 weekdays: 70.5%, 85.6%, 82.8%, and 88.0%, respectively, occurred between noon and midnight. In the model base case, total daily admitted patient boarding hours were 77.0 per day; the sensitivity analysis showed that shifting the peak inpatient discharge time 4h earlier eliminated ED boarding, and discharging 75% of inpatients by noon and discharging all inpatients between 8:00 a.m. and 4:00 p.m. both decreased boarding hours to 3.0. CONCLUSION Timing of inpatient discharges had an impact on the need to board admitted patients. This model demonstrates the potential to reduce or eliminate ED boarding by improving inpatient discharge timing in anticipation of the daily surge in ED demand for inpatient beds.


Journal of the Operational Research Society | 2005

Allocating the gains from resource pooling with the Shapley Value

Gilles Reinhardt; Maqbool Dada

To make their cost structure more efficient, firms often pool their critical resources: small divisions of a large firm may negotiate a joint contract to benefit from volume discounts; or firms may outsource their call centres to an independent provider who is able to increase utilization by reducing variability since demand is now pooled. Since pooling demand reduces total joint costs, an immediate question is how the realized savings should be shared. We model the problem as a cooperative game and use the resulting allocation schemes to distribute the savings. One popular scheme is the Shapley Value, which always exists and, we show, represents each players incremental value to the pool. When the pooled savings depend on the sum of each players demand, we label the game coalition symmetric and propose, for those games, an algorithm that makes pseudo-polynomial the computation of the Shapley Value.


Simulation in healthcare : journal of the Society for Simulation in Healthcare | 2012

Emergency department patient flow simulations using spreadsheets.

Michael G. Klein; Gilles Reinhardt

Introduction Patient flow computer simulations allow Emergency Department stakeholders to assess operational interventions, develop utilization and performance measures, and produce estimates for budgeting or planning purposes. Key challenges of traditional discrete-event computer simulation software are their inherent complexity for modeling, coding, or analyzing output and their significant costs and training. We propose a simulation platform that runs in spreadsheets. Because of their low cost, popularity and powerful functionality and performance, spreadsheets also allow for the development and management of simulations that efficiently output results that are just as reliable as those from traditional software. Methods A spreadsheet simulation is developed by modeling one row as one simulated minute (more than 20,000 rows for a 2-week period). Uncertainty in arrivals, patient type, routing, and treatment times is modeled using the “rand()” function to simulate the state of the Emergency Department at a given point in time. The patient is tracked with embedded “if()” functions and summary statistics are obtained through range functions. We use an equivalence test to determine whether the resulting average length-of-stay figures are the same as those of a traditional simulation platform. Results We find little significant difference in average length-of-stay figures between both models. Conclusions Spreadsheet simulations are as effective as traditional simulations but easier to use, understand, and implement. Spreadsheet software is widely available, at a fraction of the cost of discrete-event simulation software. Coding spreadsheet simulations may be more challenging as it requires a different and more novel expertise than traditional computer programming. However, spreadsheets can be organized to reference existing datasets, thus minimizing the burden of copying and likelihood of transcription errors and information leakage. Output analysis can also be customized with user-specific performance statistics and charts.


Journal of Sport Management | 2015

Leadership succession and performance: an application to college football.

Stephanie L. Dohrn; Yvette P. Lopez; Gilles Reinhardt

This article examines the impact of leader succession on organizational performance. We argue that both time and size of program are critical factors that need to be considered to appropriately determine the impacts of the leader succession on performance. We focus our analysis on the National Collegiate Athletic Association (NCAA) Football Bowl Subdivision (FBS) and examine the effect of performance-related coaching firings on on-field performance (win-loss percentage, Sagarin rating, Sagarin rank) and financial performance (team revenue). We cluster teams into three categories based on revenue and analyze team performance following leader succession after the first, second, and fourth year following the change. While most studies in this area report findings consistent with vicious cycle theory or ritual scapegoating, our findings offer primary support for common sense theory and ritual scapegoating, contingent on time and the size of the program as determined by team revenue.


Computing in Economics and Finance | 2004

Allocating the Cost of Congestion with the Nucleolus

Gilles Reinhardt

A natural approach to solve resource sharing problems is to model them ascooperative games and use the results to allocate the costs of the sharedresource. The nucleolus, a solution concept derived from cooperative gametheory, requires an exponential number of computations since the solution mustadhere to individual and coalitional rationality conditions. Littlechild(1974) provides a linear algorithm which produces the nucleolus of a costallocation game when the cost of a coalition is the cost of the largest playerin that coalition. In this paper, we show that for a large class of congestioncost allocation games, where each player has an independent impact on theshared resource, we can nonetheless bypass all the computational complexityand derive allocations in closed form.


Informs Transactions on Education | 2014

Case---Take Me Out Of The Ball Game

Amit Pazgal; Gilles Reinhardt

When the Chicago Cubs™ finish playing an afternoon baseball game at Wrigley Field, their home stadium, tens of thousands of fans start heading for the neighboring train station, the “Addison Red Line el stop,” and often experience very long delays before boarding their train home.


Informs Transactions on Education | 2014

Case Article---Take Me Out Of The Ball Game

Amit Pazgal; Gilles Reinhardt

This paper describes a teaching case in which students model crowd management using process analysis. The case study consists of a classroom exercise that provides a practical illustration of the steps required to analyze a process, the need for abstraction in modeling a process, and an understanding of the relationship between process metrics and their managerial implications. The students are expected to behave as city planning consultants, addressing the long lines fans regularly face when getting home at the end of a Chicago Cubs™ baseball game. The case requires them to use knowledge from operations, economics, and process analysis classes to model, analyze and provide concrete solutions to alleviate crowding. Case Teaching Note: Interested Instructors please see the Instructor Materials page for access to the restricted materials. To maintain the integrity and usefulness of cases published in ITE, unapproved distribution of the case teaching notes and other restricted materials to any other party is prohibited.

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Sunil Chopra

Northwestern University

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Julia C McLeod

Johns Hopkins University

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