Economics

Permanent URI for this collectionhttps://hdl.handle.net/10679/316

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Open Access
Fragile transitions from education to employment Youth, gender and migrant status in the EU
(Taylor & Francis, 2019) Çelik, Ç.; Gökşen, F.; Filiztekin, Orhan Alpay; Öker, İ.; Smith, M.; Economics; FİLİZTEKİN, Orhan Alpay
N/A
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Global trends in liquidity creation: The role of the off-balance sheet
(Peter Lang AG, 2019-03-28) Akın, Özlem; Özsoy, Satı Mehmet; Economics; International Finance; PARLAYAN, Özlem Akın; ÖZSOY, Satı Mehmet
Banks create liquidity by transforming liquid liabilities into illiquid assets and this is one of their main functions. Yet excessive liquidity creation, especially via off-balance sheet activities, might have contributed to the 2008-2009 financial crisis. In this chapter, we analyze the dynamics of liquidity creation in Turkey and the United States, and the contribution of off-balance sheet activities therein.
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Characterizing the TTC rule via pair-efficiency: A short proof
(Elsevier, 2024-01) Ekici, Özgün; Sethuraman, J.; Economics; EKİCİ, Özgün
In the object reallocation problem, Ekici (2023) showed that Top Trading Cycles (TTC) is the unique rule that is strategyproof, individual-rational, and pair-efficient. We provide a short proof of this characterization result.
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Production planning with flexible manufacturing systems under demand uncertainty
(Taylor & Francis, 2024) Elyasi, M.; Özener, Başak Altan; Ekici, Ali; Özener, Okan Örsan; Economics; Industrial Engineering; ÖZENER, Başak Altan; EKİCİ, Ali; ÖZENER, Okan Örsan
This paper delves into the impacts of an ongoing global crisis on the resilience of supply chains. Furthermore, it proposes measures to address and mitigate the disruptions caused by the prevailing uncertainties. For example, while the economy has started to recover after the pandemic and demand has increased, companies have not fully returned to their pre-pandemic levels. To enhance their supply chain resilience and effectively manage disruptions, one viable strategy is the implementation of flexible/hybrid manufacturing systems. This research is motivated by the specific requirements of Vestel Electronics, a household appliances company, which seeks a flexible/hybrid manufacturing production setup involving dedicated machinery to meet regular demand and the utilisation of flexible manufacturing system (FMS) to handle surges in demand. We employ a scenario-based approach to model demand uncertainty, enabling the company to make immediate and adaptive decisions that take advantage of the cost-effectiveness of standard production and the responsiveness of FMS. To solve the problem, we propose a heuristic algorithm based on column generation. The numerical results demonstrate that our optimisation model provides solutions with an average optimality gap of less than 6% while also reducing the average cost of standard production schemes without FMS by over 12%.
Open Access
Understanding household healthcare expenditure can promote health policy reform
(Cambridge University Press, 2023) Best, R.; Tuncay Alpanda, Berna; Economics; ALPANDA, Berna Tuncay
Studies of health care expenditure often exclude explanatory variables measuring wealth, despite the intuitive importance and policy relevance. We use the Household, Income and Labour Dynamics in Australia Survey to assess impacts of income and wealth on health expenditure. We investigate four different dependent variables related to health expenditure and use three main methodological approaches. These approaches include a first difference model and introduction of a lagged dependent variable into a cross-sectional context. The key findings include that wealth tends to be more important than income in identifying variation in health expenditure. This applies for health variables which are not directly linked to means testing, such as spending on health practitioners and for being unable to afford required medical treatment. In contrast, the paper includes no evidence of different impacts of income and wealth on spending on medicines, prescriptions or pharmaceuticals. The results motivate two novel policy innovations. One is the introduction of an asset test for determining rebate eligibility for private health insurance. The second is greater focus on asset testing, rather than income tests, for a wide range of general welfare payments that can be used for health expenditure. Australia's world-leading use of means testing can provide a test case for many countries.
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Transition dynamics in equilibrium search
(American Economic Association, 2022) Akın, Şerife Nuray; Platt, B. C.; Economics; DURAN, Şerife Nuray
We study a dynamic equilibrium search model where sellers differ in their urgency to liquidate an asset. Buyers strategically make price offers without knowing a given seller’s urgency. We study liquidity and price dynamics on the transition path after an unexpected shock. Generically, the transition includes a phase where all buyers offer the same price, causing a market collapse; however, price dispersion resumes in finite time, leading to a recovery where both types make sales. We show that prices and liquidity can overshoot before converging to the steady state. When relaxed sellers randomly become desperate, dampening oscillations can occur.
Open Access
On optimal toll design for bosporus crossings
(Sosyoekonomi Society, 2022-10) Ekici, Özgün; Economics; EKİCİ, Özgün
For many years, two toll bridges served commuter demand to cross the strait called Bosporus in Istanbul, Turkey. An underground connection called the Eurasian tunnel had been recently launched to relieve the strait's traffic. We study a simple transportation model that incorporates the forces that have come into play after the opening of the Eurasian tunnel. We find that for welfare maximisation, the premium paid for using the tunnel should be fixed in the two directions and not excessive. The current toll regime violates these features, and we recommend its amendment in light of our findings.
Open Access
On approximate Nash equilibria of the two-source connection game
(TÜBİTAK, 2022) Çaşkurlu, B.; Açikalin, U. U.; Kizilkaya, F. E.; Ekici, Özgün; Economics; EKİCİ, Özgün
The arbitrary-sharing connection game is prominent in the network formation game literature [1]. An undirected graph with positive edge weights is given, where the weight of an edge is the cost of building it. An edge is built if agents contribute a sufficient amount for its construction. For agent i, the goal is to contribute the least possible amount while assuring that the source node si is connected to the terminal node ti. In this paper, we study the special case of this game in which there are only two source nodes. In this setting, we prove that there exists a 2-approximate Nash equilibrium that is socially optimal. We also consider the further special case in which there are no auxiliary nodes (i.e., every node is a terminal or source node). In this further special case, we show that there exists a 3/2 -approximate Nash equilibrium that is socially optimal. Moreover, we show that it is computable in polynomial time.
Open Access
Stochastic production planning with flexible manufacturing systems and uncertain demand: A column generation-based approach
(Elsevier, 2022) Elyasi, Milad; Özener, Başak Altan; Ekici, Ali; Özener, Okan Örsan; Yanıkoğlu, İhsan; Economics; Industrial Engineering; ÖZENER, Başak Altan; EKİCİ, Ali; ÖZENER, Okan Örsan
The ongoing pandemic, namely COVID-19, has rendered widespread economic disorder. The deficiencies have delayed production at manufacturers in several industries on the supply side. The effects of disruption were more notable for industries with longer supply chains, especially reaching East Asia. Regarding the demand, sectors can be divided into three categories: i) the ones, like e-commerce companies, that experienced augmented demand; ii) the ones with a plunged demand, like what hotels and restaurants experience; iii) the companies experiencing a roller-coaster-ride business. After mitigation efforts, the economy started recovering, resulting in increased demand. However, regardless of their struggles, the companies have not fully returned to their pre-pandemic levels. One of the strategies to gain resilience in its supply chain and manage the disruptions is to employ flexible/hybrid manufacturing systems. This paper considers a flexible/hybrid manufacturing production setting with typically dedicated machinery to satisfy regular demand and a flexible manufacturing system (FMS) to handle surge demand. We model the uncertainty in demand using a scenario-based approach and allow the business to make here-and-now and wait-and-see decisions exploiting the cost-effectiveness of the standard production and responsiveness of the FMS. We propose a column generation-based algorithm as the solution approach. Our computational analysis shows that this hybrid production setting provides highly robust response to the uncertainty in demand, even with high fluctuations.
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On existence of equilibrium under social coalition structures
(Cambridge University Press, 2022-02) Caskurlu, B.; Ekici, Özgün; Kizilkaya, F. E.; Economics; EKİCİ, Özgün
In a strategic-form game, a strategy profile is an equilibrium if no viable coalition of agents (or players) benefits (in the Pareto sense) from jointly changing their strategies. Weaker or stronger equilibrium notions can be defined by considering various restrictions on coalition formation. For instance, in a Nash equilibrium, it is assumed that viable coalitions are singletons, and in a super strong equilibrium, it is assumed that every coalition is viable. Restrictions on coalition formation can be justified by communication limitations, coordination problems, or institutional constraints. In this paper, inspired by social structures in various real-life scenarios, we introduce certain restrictions on coalition formation, and on their basis, we introduce a number of equilibrium notions. As an application, we study our equilibrium notions in resource selection games (RSGs), and we present a complete set of existence and nonexistence results for general RSGs and their important special cases.
Open Access
Games with switching costs and endogenous references
(Wiley, 2022-05-25) Güney, Begüm; Richter, M.; Economics; GÜNEY, Begüm
We introduce a game-theoretic model with switching costs and endogenous references. An agent endogenizes his reference strategy, and then taking switching costs into account, he selects a strategy from which there is no profitable deviation. We axiomatically characterize this selection procedure in one-player games. We then extend this procedure to multiplayer simultaneous games by defining a Switching Cost Nash Equilibrium (SNE) notion, and prove that (i) an SNE always exists; (ii) there are sets of SNE, which can never be a set of Nash equilibrium for any standard game; and (iii) SNE with a specific cost structure exactly characterizes the Nash equilibrium of nearby games, in contrast to Radner's (1980) ε-equilibrium. Subsequently, we apply our SNE notion to a product differentiation model, and reach the opposite conclusion of Radner (1980): switching costs for firms may benefit consumers. Finally, we compare our model with others, especially Köszegi and Rabin's (2006) personal equilibrium.
Open Access
Inequalities in the geographical distribution and workload of obstetrics and gynaecology specialists by gender in Turkey
(World Health Organization, 2022-06) Erus, B.; Tuncay Alpanda, Berna; Economics; ALPANDA, Berna Tuncay
Background: Women often have a preference for female obstetrics and gynaecology specialists (ob/gyns). Following the policy allowing physician selection by patients in Turkey, distribution of ob/gyns by gender across provinces has been an important indicator of access to healthcare. Aims: To analyse ob/gyns distribution by gender across provinces in Turkey, with emphasis on the relationship with conservativeness of the province and resulting physician workload. Methods: We measured the number of male and female ob/gyns by province in 2016 and the number of outpatient visits and deliveries performed by male and female ob/gyns in 2015. Pearson and Spearman correlation of the female ratio with votes for conservative parties was used to assess the distribution of ob/gyns. We then analysed the correlation with resulting workload of female ob/gyns and ran linear regressions of these variables controlling the number of ob/gyns in a province. Results: More conservative provinces, measured by the vote share for conservative political parties, have a higher ratio of female ob/gyns. Linear regression showed that a 1 percentage point (pp) increase in the vote share corresponded to a 0.69 pp increase in female ratio. For workload, a 1 pp higher female ratio resulted in a decrease in workload, measured as outpatient visits per female ob/gyn divided by that per male ob/gyn, by 0.014. Conclusion: Conservative provinces have more female ob/gyns, but other provinces compensate for that with higher female ob/gyn workload. High workload may have adverse health effects and result in lower quality of care.
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Relating dynamic test capacity, digital tracking of countries and COVID-19 Performance: A cross-country study
(Peter Lang AG, 2022-10-05) Tuncay Alpanda, Berna; Özen, İ. C.; Economics; Ayhan, Fatih; Darıcı, Burak; ALPANDA, Berna Tuncay
N/A
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Shelter from the storm: health service access and utilization among Syrian refugees in Turkey
(Springer, 2022-11) Tuncay Alpanda, Berna; Özen, İ. C.; Bump, J. B.; Economics; ALPANDA, Berna Tuncay
Aim: Since 2011, the conflict in Syria has led to the migration of 5.6 million refugees, mainly to neighbouring countries. By the start of 2019, over 3.5 million people had moved to Turkey to seek safety, meaning that Turkey is hosting the majority of these refugees. Most of them are today settled in urban and peri-urban locations. A large part of the health services of these populations had been cut before their move, leaving a significant population that had been unprotected and under-provided for. The Turkish health system has provided a cost-free way for these populations to use health services, especially public health services at the primary and secondary levels. The objective of this study was to identify the size and the geography of the health shock as a result of the Syrian influx, starting in 2011. The resulting health effects of the refugee integration and the resilience of the health system are also assessed. Subject and methods: We investigated the medical treatment given in public hospitals for the Syrian population for the years 2012–2014, at the primary and secondary health levels. We investigated 10,444,290 cases of health visits, 7,211,342 of them occurring at the secondary level and representing more than 70% of total applications. The overall coverage of the health system for the Syrian population is estimated to be 64%, with 115,000 live-births among Syrian refugees occurring in the same time period. Results: Since the influx of Syrian refugees, there has been a considerable shock to the regional part of the Turkish health system located closest to the Syrian border. From the Syrian refugee point of view, no significant over-crowding or lowered quality effect was observed in the health system. The Syrian refugee’s health demand was observed to be different from that of the Turkish average, as this population’s unique vulnerabilities and access evolution came to the fore. However, significant convergence was then observed in the health demand, as urgent needs were converted into more routine health requirements over time. Conclusion: This initial investigation of the Turkish health system after the Syrian integration underlies the case for a significant resilience being shown, especially in areas where it has been most severely tested.
Open Access
Price and quality decisions of a service provider under heterogeneous demand
(Boğaziçi Üniversitesi, 2019) Özener, Başak Altan; Atahan, Pelin; Economics; Sectoral Education and Professional Development; ÖZENER, Başak Altan; DEMİRCİLER, Pelin Atahan
A monopolist service provider's quality and price decisions are analyzed in a vertically differentiated market where customers demand different quantities of a service. We find that depending on the relative sizes of the market segments and the difference in the valuations of different customers, the service provider may find it optimal to either offer a non-discriminating service or a discriminating service serving only high-valuation customers. The service provider never finds it optimal to serve the market segments that have low-valuation for quality when the discrimination strategy is optimal. © 2019 Bogazici Universitesi. All rights reserved.
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On singleton congestion games with resilience against collusion
(Springer, 2021) Caskurlu, B.; Ekici, Özgün; Kızılkaya, F. E.; Economics; EKİCİ, Özgün
We study the subclass of singleton congestion games in which there are identical resources with increasing cost functions. In this domain, we prove that there always exists an outcome that is resilient to weakly-improving deviations by singletons (i.e., the outcome is a Nash equilibrium), by the grand coalition (i.e., the outcome is Pareto efficient), and by coalitions with respect to an a priori given partition coalition structure (i.e., the outcome is a partition equilibrium). To our knowledge, this is the strongest existence guarantee in the literature on congestion games when weakly-improving deviations are considered. Our proof technique gives the false impression of a potential function argument but it is a novel application of proof by contradiction.
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A game theoretical approach for improving the operational efficiencies of less-than-truckload carriers through load exchanges
(Springer, 2021-09) Özener, Başak Altan; Özener, Okan Örsan; Economics; Industrial Engineering; ÖZENER, Başak Altan; ÖZENER, Okan Örsan
Less-than-truckload (LTL) transportation offers fast, flexible and relatively low-cost transportation services to shippers. In order to cope with the effects of economic recessions, the LTL industry implemented ideas such as reducing excess capacity and increasing revenues through better yield management. In this paper, we extend these initiatives beyond the reach of individual carriers and propose a collaborative framework that facilitates load exchanges to reduce the operational costs. Even though collective solutions are proven to provide benefits to the participants by reducing the inefficiencies using a system-wide perspective, such solutions are often not attainable in real-life as the negotiating parties are seeking to maximize their individual profits rather than the overall profit and also they are unwilling to share confidential information. Therefore, a mechanism that enables collaboration among the carriers should account for the rationality of the individual participants and should require minimal information transfer between participants. Having this in mind, we propose a mechanism that facilities collaboration through a series of load exchange iterations and identifies an equilibrium among selfish carriers with limited information transfer among the participants. Our time-efficient mechanism can handle large instances with thousands of loads as well as provide significant benefits over the non-collaborative management of LTL networks.
Open Access
Welfare and research and development incentive effects of uniform and differential pricing schemes
(Springer, 2021-09-22) Gnecco, G.; Pammolli, F.; Tuncay Alpanda, Berna; Economics; ALPANDA, Berna Tuncay
This paper is about the application of optimization methods to the analysis of three pricing schemes adopted by one manufacturer in a two-country model of production and trade. The analysis focuses on pricing schemes—one uniform pricing scheme, and two differential pricing schemes—for which there is no competition coming from the so-called parallel trade. This term denotes the practice of buying a patented product like a medicine in one market at one price, then re-selling it in a second so-called gray market at a higher price, on a parallel distribution chain where it competes with the official distribution chain. The adoption of pricing schemes under which parallel trade does not arise can prevent the occurrence of its well-documented negative effects. In the work, a comparison of the optimal solutions to the optimization problems modeling the three pricing schemes is performed. More specifically, conditions are found under which the two differential pricing schemes are more desirable from several points of view (e.g., incentive for the manufacturer to do Research and Development, product accessibility, global welfare) than the uniform pricing scheme. In particular, we prove that, compared to the uniform pricing scheme, the two differential pricing schemes increase the incentive for the manufacturer to invest in Research and Development. We also prove that they serve both countries under a larger range of values for the relative market size, making the product more accessible to consumers in the lower price country. Moreover, we provide a sufficient condition under which price discrimination is more efficient from a global welfare perspective than uniform pricing. The analysis applies in particular to the case of the European Single Market for medicines. Compared to other studies, our work takes into account also the possible presence in all the optimization problems of a positive constant marginal cost of production, showing that it can have non-negligible effects on the results of the analysis. As an important contribution, indeed, our analysis clarifies the conditions—which have been overlooked in the literature about the mechanisms adopted to prevent parallel trade occurrence—that allow/do not allow one to neglect the presence of this factor. Such conditions are related, e.g., to the comparison between the positive constant marginal cost of production, the parallel trade cost per-unit, and the maximal price that can be effectively charged to the consumers in the lower price country.
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The effect of hosting 3.4 million refugees on native population mortality
(Elsevier, 2021-12) Aygün, A.; Kırdar, M. G.; Tuncay Alpanda, Berna; Economics; ALPANDA, Berna Tuncay
As of the end of 2017, 3.4 million Syrian refugees lived in Turkey. These refugees left a country where the health system was utterly broken. Several studies report that Syrian refugees faced numerous diseases during their exodus, brought certain infectious diseases to the hosting communities, and have a high incidence of health care utilization. Moreover, they have much higher fertility rates than natives. We examine the effect of Syrian refugees on the health care resources in Turkey and on natives’ mortality—with a focus on infant, child, and elderly mortality. Our OLS results yield suggestive evidence of an adverse effect of the refugee shock on infant and child mortality. However, we find that this is a result of endogenous settlement patterns of refugees. Once we account for the endogeneity using a plausibly exogenous instrument, we find no evidence of an effect on native mortality for any age group. We also analyze the refugees’ pressure on the health care services in Turkey and the government's response to understand our findings on mortality outcomes.
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On existence of equilibrium under social coalition structures
(Springer, 2020) Caskurlu, B.; Ekici, Özgün; Kizilkaya, F. E.; Economics; Chen, J.; Feng, Q.; Xu, J.; EKİCİ, Özgün
In a strategic form game, a strategy profile is an equilibrium if no viable coalition of agents benefits (in the Pareto sense) from jointly changing their strategies. Weaker or stronger equilibrium notions can be defined by considering various restrictions on coalition formation. In a Nash equilibrium, for instance, the assumption is that viable coalitions are singletons, and in a super strong equilibrium, every coalition is viable. Restrictions on coalition formation can be justified by communication, coordination or institutional constraints. In this paper, inspired by social structures in various real-life scenarios, we introduce certain restrictions on coalition formation, and on their basis, we introduce a number of equilibrium notions. We study our equilibrium notions in resource selection games (RSGs), and we present a complete set of existence and non-existence results for general RSGs and their important special cases.

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