@article{gu_heese_kemahlioglu-ziya_ziya_2024, title={Pricing for services with cross-segment externalities, capacity constraints, and competition}, volume={313}, ISSN={["1872-6860"]}, DOI={10.1016/j.ejor.2023.09.021}, abstractNote={In many service systems such as movie theaters, sports clubs, or hotels, different customer segments share physical space, and the presence of customers from different segments may affect the utility a customer receives from the service. We consider a setting where two competing facilities offer service to two distinct types of customers and study whether and when the firms can benefit from using differential pricing. The two firms do not explicitly decide whether to use uniform or differential pricing. Rather, we derive our findings by characterizing and comparing all equilibria that might arise when differential pricing is feasible. Our results suggest that if the network externalities are symmetric, that is, if the two customer segments feel equally about the presence of customers of the other segment, then the firms never benefit from price differentiation, unless the network externalities are negative and strong when compared to the travel/inconvenience cost that the customers incur when receiving service from their less preferred facility. Interestingly, we find that using differential pricing can even hurt firm profits, when it leads to fierce price competition between the two service providers.}, number={2}, journal={EUROPEAN JOURNAL OF OPERATIONAL RESEARCH}, author={Gu, Wei and Heese, H. Sebastian and Kemahlioglu-Ziya, Eda and Ziya, Serhan}, year={2024}, month={Mar}, pages={801–813} }
 @article{heese_kemahlioglu-ziya_2023, title={Capacity shortages, regulation, and firm incentives in the generic drugs industry}, volume={6}, ISSN={["1520-6750"]}, DOI={10.1002/nav.22132}, abstractNote={Drug shortages are becoming more frequent and severe in the United States, especially for generic drugs. A lack of economic incentives has been cited as a root cause. Only few firms choose to produce a such drugs, and, if they do, these firms do not allocate large levels of capacity. Hence, total industry supply is limited, increasing the odds of shortages. We develop and analyze a stylized game‐theoretic model of a generic drug market to understand the impact of various governmental interventions on the total industry equilibrium supply. We explicitly consider firm market entry and exit decisions and the participating firms' incentives to allocate productive capacity to the focal drug market. We first characterize sustainable numbers of active drug manufacturers and their equilibrium capacity allocation decisions for a given regulatory environment. We then analyze the effects of different possible policy interventions on these equilibrium decisions and total industry capacity. Finally, we consider the impact of combinations of different interventions and, importantly, the sequence in which such combined interventions are introduced. A key result of our analysis is that the sequence of policy interventions may have an important effect on the resulting equilibrium industry capacity. When changing the regulatory environment, policymakers should be careful never to lead a sequence of changes with an adjustment that adversely affects pharmaceutical firms' incentives to allocate capacity to the focal drug market; we show that starting with capacity‐supporting interventions always is a dominant strategy when aiming to increase total industry capacity.}, journal={NAVAL RESEARCH LOGISTICS}, author={Heese, H. Sebastian and Kemahlioglu-Ziya, Eda}, year={2023}, month={Jun} }
 @article{sahebi-fakhrabad_kemahlioglu-ziya_handfield_wood_patel_page_chang_2023, title={In-Hospital Code Status Updates: Trends Over Time and the Impact of COVID-19}, volume={12}, ISSN={["1938-2715"]}, DOI={10.1177/10499091231222188}, abstractNote={OBJECTIVE
The primary objective was to evaluate if the percentage of patients with missing or inaccurate code status documentation at a Trauma Level 1 hospital could be reduced through daily updates. The secondary objective was to examine if patient preferences for DNR changed during the COVID-19 pandemic.


METHODS
This retrospective study, spanning March 2019 to December 2022, compared the code status in ICU and ED patients drawn from two data sets. The first was based on historical electronic medical records (EHR), and the second involved daily updates of code status following patient admission.


RESULTS
Implementing daily updates upon admission was more effective in ICUs than in the ED in reducing missing code status documentation. Around 20% of patients without a specific code status chose DNR under the new system. During COVID-19, a decrease in ICU patients choosing DNR and an increase in full code (FC) choices were observed.


CONCLUSION
This study highlights the importance of regular updates and discussions regarding code status to enhance patient care and resource allocation in ICU and ED settings. The COVID-19 pandemic's influence on shifting patient preferences towards full code status underscores the need for adaptable documentation practices. Emphasizing patient education about DNR implications and benefits is key to supporting informed decisions that reflect individual health contexts and values. This approach will help balance the considerations for DNR and full code choices, especially during health care crises.}, journal={AMERICAN JOURNAL OF HOSPICE & PALLIATIVE MEDICINE}, author={Sahebi-Fakhrabad, Amirreza and Kemahlioglu-Ziya, Eda and Handfield, Robert and Wood, Stacy and Patel, Mehul D. and Page, Cristen P. and Chang, Lydia}, year={2023}, month={Dec} }
 @article{sahebi-fakhrabad_sadeghi_kemahlioglu-ziya_handfield_tohidi_vasheghani-farahani_2023, title={The Impact of Opioid Prescribing Limits on Drug Usage in South Carolina: A Novel Geospatial and Time Series Data Analysis}, volume={11}, ISSN={["2227-9032"]}, url={https://doi.org/10.3390/healthcare11081132}, DOI={10.3390/healthcare11081132}, abstractNote={The opioid crisis in the United States has had devastating effects on communities across the country, leading many states to pass legislation that limits the prescription of opioid medications in an effort to reduce the number of overdose deaths. This study investigates the impact of South Carolina’s prescription limit law (S.C. Code Ann. 44-53-360), which aims to reduce opioid overdose deaths, on opioid prescription rates. The study utilizes South Carolina Reporting and Identification Prescription Tracking System (SCRIPTS) data and proposes a distance classification system to group records based on proximity and evaluates prescription volumes in each distance class. Prescription volumes were found to be highest in classes with pharmacies located further away from the patient. An Interrupted Time Series (ITS) model is utilized to assess the policy impact, with benzodiazepine prescriptions as a control group. The ITS models indicate an overall decrease in prescription volume, but with varying impacts across the different distance classes. While the policy effectively reduced opioid prescription volumes overall, an unintended consequence was observed as prescription volume increased in areas where prescribers were located at far distances from patients, highlighting the limitations of state-level policies on doctors. These findings contribute to the understanding of the effects of prescription limit laws on opioid prescription rates and the importance of considering location and distance in policy design and implementation.}, number={8}, journal={HEALTHCARE}, author={Sahebi-Fakhrabad, Amirreza and Sadeghi, Amir Hossein and Kemahlioglu-Ziya, Eda and Handfield, Robert and Tohidi, Hossein and Vasheghani-Farahani, Iman}, year={2023}, month={Apr} }
 @article{heese_kemahlioglu-ziya_perdikaki_2021, title={Outsourcing under Competition and Scale Economies: When to Choose a Competitor as a Supplier}, volume={52}, ISSN={["1540-5915"]}, DOI={10.1111/deci.12449}, abstractNote={ABSTRACT In highly competitive industries, many original equipment manufacturers (OEMs) increasingly outsource production to reduce costs. We study an OEM's outsourcing decision between a third‐party supplier and a vertically integrated firm that manufactures in house and competes with the OEM in the consumer market (i.e., an integrated competitor). Our setting explicitly considers two important aspects of the sourcing decision. First, we capture the competition between the two sourcing alternatives through interdependent repeated bilateral wholesale‐price negotiations in which the negotiating parties' disagreement payoffs are endogenous. Specifically, in the negotiation between the OEM and either supplier, the negotiating parties' disagreement payoffs are given by the profits that would result if the OEM sourced from the other supplier. Second, we capture the economies of scale involved with production in that either supplier derives positive externalities from increasing his total production quantity. We show that, for given wholesale prices—counter to intuition—it is not optimal for the OEM to always choose the supplier offering the lower wholesale price. In the absence of either competition or economies of scale, the OEM always simply prefers the source with the lower wholesale price. However, in the presence of both economies of scale and competition in the focal market, the OEM may be better off sourcing from the third‐party supplier even at a higher wholesale price. When equilibrium wholesale prices are determined through simultaneous bilateral negotiations between the OEM and the two potential suppliers, sourcing from the integrated competitor might be more profitable when scale economies are strong and competition is weak. We investigate the robustness of our findings and find that our structural results continue to hold for several model relaxations and extensions. We also show that in the absence of restrictive capacity constraints, the OEM always prefers sourcing exclusively from one of the suppliers to dual sourcing. Our findings demonstrate the importance for managers to account for both the extent of scale economies and the competitive dynamics in the consumer market when deciding their supply mode.}, number={5}, journal={DECISION SCIENCES}, author={Heese, Hans Sebastian and Kemahlioglu-Ziya, Eda and Perdikaki, Olga}, year={2021}, month={Oct}, pages={1209–1241} }
 @article{jaunich_decarolis_handfield_kemahlioglu-ziya_ranjithan_moheb-alizadeh_2020, title={Life-cycle modeling framework for electronic waste recovery and recycling processes}, volume={161}, ISSN={["1879-0658"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85086084470&partnerID=MN8TOARS}, DOI={10.1016/j.resconrec.2020.104841}, abstractNote={Policies and regulations such as Extended Producer Responsibility (EPR) have been implemented to potentially increase the recycling rate of electronic waste (e-waste), but the cost and environmental impacts of associated collection, transportation, material recovery, material re-processing, and disposal could outweigh the benefits of recycling if the e-waste management system is not effectively designed and implemented. This paper presents a quantitative, holistic framework to systematically estimate life-cycle impacts and costs associated with e-waste management. This new framework was tested using data from the state of Washington's EPR program to represent e-waste collection, transportation, processing and disposal. Sensitivity of process-level life-cycle model outputs to parameter and input variability was also conducted. Drop-off using fossil-fuel-powered personal vehicles was found to be a key contributor to cost and carbon dioxide emissions. Decision-makers must account for drop-off and consider the feasibility of alternate e-waste aggregation strategies to ensure life-cycle benefits of e-waste recycling are maximized.}, journal={RESOURCES CONSERVATION AND RECYCLING}, author={Jaunich, Megan Kramer and DeCarolis, Joseph and Handfield, Robert and Kemahlioglu-Ziya, Eda and Ranjithan, S. Ranji and Moheb-Alizadeh, Hadi}, year={2020}, month={Oct} }
 @article{heese_kemahlıoğlu-ziya_2016, title={Don't ask, don't tell: Sharing revenues with a dishonest retailer}, volume={248}, ISSN={0377-2217}, url={http://dx.doi.org/10.1016/j.ejor.2015.07.054}, DOI={10.1016/j.ejor.2015.07.054}, abstractNote={When different supply chain parties have private information, some form of information sharing is required to improve supply chain performance. However, it might be difficult to ensure truthful information transfer when firms can benefit from distorting their private information. To investigate the impact of dishonest information transfer, we consider a single-supplier single-retailer supply chain that operates under a contract with a revenue sharing clause, providing the retailer incentive to underreport sales revenues. In practice, suppliers utilize audits based on statistical tools that, for example, compare the retailers’ sales reports and order quantities to limit, but not necessarily eliminate, cheating. We investigate the impact of such limited cheating on the different supply chain constituents. We show that when the retailer can exert sales effort, a supplier might benefit from the retailer's dishonesty. Our findings also suggest that if the retailer's negotiation power is high or if retailer effort is effective, the supplier should reduce the retailer's revenue share and absorb some of the demand risk to increase retailer participation. When facing a less powerful or less capable retailer, the supplier might be better off extracting profitability upfront through a higher wholesale price.}, number={2}, journal={European Journal of Operational Research}, publisher={Elsevier BV}, author={Heese, H. Sebastian and Kemahlıoğlu-Ziya, Eda}, year={2016}, month={Jan}, pages={580–592} }
 @article{esenduran_kemahlioglu-ziya_swaminathan_2016, title={Take-Back Legislation: Consequences for Remanufacturing and Environment}, volume={47}, ISSN={["1540-5915"]}, DOI={10.1111/deci.12174}, abstractNote={In the last two decades, many countries have enacted product take-back legislation that holds manufacturers responsible for the collection and environmentally sound treatment of end-of-use products. In an industry regulated by such legislation, we consider a manufacturer that also sells remanufactured products under its brand name. Using a stylized model, we consider three levels of legislation: no take-back legislation, legislation with collection targets, and legislation with collection and reuse targets. We characterize the optimal solution for the manufacturer and analyze how various levels of legislation affect manufacturing, remanufacturing, and collection decisions. First, we explore whether legislation with only collection targets causes an increase in remanufacturing levels, which is argued to be an environmentally friendlier option for end-of-use treatment than other options such as recycling. While increased remanufacturing alone is usually perceived as a favorable environmental outcome, if one considers the overall environmental impact of new and remanufactured products, this might not be the case. To study this issue, we model the environmental impact of the product following a life cycle analysis–based approach. We characterize the conditions under which increased remanufacturing due to take-back legislation causes an increase in total environmental impact. Finally, we model the impact of legislation on consumer surplus and manufacturer profits and identify when total welfare goes down because of legislation.}, number={2}, journal={DECISION SCIENCES}, author={Esenduran, Goekce and Kemahlioglu-Ziya, Eda and Swaminathan, Jayashankar M.}, year={2016}, month={Apr}, pages={219–256} }
 @article{esenduran_kemahlioglu-ziya_2015, title={A Comparison of Product Take-Back Compliance Schemes}, volume={24}, ISSN={["1937-5956"]}, DOI={10.1111/poms.12213}, abstractNote={ Product take‐back regulation, under which firms finance the collection and treatment of their end‐of‐life products, is a widely used environmental program. One of the most common compliance schemes is collectively with cost allocation by market share. As an alternative, individual compliance scheme is considered. Assuming that firms can choose their compliance scheme, we compare these two schemes with respect to the costs they impose on firms and environmental benefits. We show that high collection targets and large market shares among firms in a collective compliance scheme make it more cost‐effective. From an environmental benefits perspective, the prevailing intuition is that collection rates will be higher under collective schemes but individual compliance will provide more incentive for higher recyclability levels. Our results challenge both of these premises. We identify conditions under which collection rates are higher when firms comply individually and recyclability levels are higher when firms comply collectively and allocate costs with respect to market shares. }, number={1}, journal={PRODUCTION AND OPERATIONS MANAGEMENT}, author={Esenduran, Goekce and Kemahlioglu-Ziya, Eda}, year={2015}, month={Jan}, pages={71–88} }
 @article{heese_kemahlioglu-ziya_2013, title={Enabling Opportunism: Revenue Sharing when Sales Revenues are Unobservable}, volume={23}, ISSN={1059-1478}, url={http://dx.doi.org/10.1111/poms.12163}, DOI={10.1111/poms.12163}, abstractNote={ We consider a supply chain with a supplier that sells to a retailer under a revenue‐sharing arrangement. Demand is uncertain and unobservable to the supplier. We assume that the retailer is rational, that is, the retailer behaves opportunistically and underreports sales revenues to the supplier whenever such underreporting is profitable. Assuming the supplier has the ability to audit the retailer and learn about the actual sales revenues, we show that the supplier will never find it optimal to audit to the point that ensures truthful reporting for all demand realizations. By committing to an auditing policy, the supplier can exploit retailer opportunism and derive profits that at times even exceed those that could be obtained when dealing with a retailer that always strictly adheres to the agreed‐upon contract terms. We also show that the retailer's opportunistic behavior can increase total supply chain profits. }, number={9}, journal={Production and Operations Management}, publisher={Wiley}, author={Heese, H. Sebastian and Kemahlioglu-Ziya, Eda}, year={2013}, month={Nov}, pages={1634–1645} }