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Publication Open Access A characterization of the extended serial correspondence(Elsevier, 2015) Heo, Eun Jeong; Department of Economics; Yılmaz, Özgür; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 108638We study the problem of assigning objects to a group of agents. We focus on probabilistic methods that take agents' ordinal preferences over the objects. Importantly, we allow for indifferences among objects. Katta and Sethuraman (2006) propose the extended serial correspondence to solve this problem. Our main result is a characterization of the extended serial correspondence in welfare terms by means of stochastic dominance efficiency, stochastic dominance no-envy and "limited invariance," a requirement we adapt from Heo (2014a). We also prove that an assignment matrix is selected by the extended serial correspondence if and only if it satisfies "non-wastefulness" and "ordinal fairness," which we adapt from Kesten et al.Publication Open Access A Twitter-based economic policy uncertainty index: expert opinion and financial market dynamics in an emerging market economy(Frontiers, 2022) Altuğ, Sumru; Department of Economics; Yeşiltaş, Sevcan; Şen, Anıl; Arslan, Beyza; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; Graduate School of Social Sciences and Humanities; 258768; N/A; N/AIn this paper, we construct a Twitter-based high-frequency Economic Policy Uncertainty (TEPU) index built on a select set of Twitter user accounts whose tweets are considered to reflect expert opinion on the topic. We study the relationship between the TEPU index and a set of key financial indicators for tracking financial developments in Turkey over the sample period 2013–2021. Based on the results from a vector autoregressive analysis, we find evidence that changes in expert opinion described by fluctuations in the TEPU index interact with fluctuations in financial indicators such as the exchange rate and the stock market index to capture information about high frequency events during our sample period. Second, fluctuations in the TEPU index emerge as a key indicator that helps to predict the country risk premium measured by the CDS spread. We also find evidence that the conditional volatility of the different series reflects salient events that occurred over our sample period.
Publication Metadata only Anlysis of attrition patterns in the Turkish household labor force survey(Orta Doğu Teknik Üniversitesi / Middl East Technical Univesity, 2009) Department of Economics; Tunalı, Fehmi İnsan; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 105635This article offers an econometric analysis of attrition patterns in the "New" Turkish Household Labor Force Survey which has been conducted since 2000. A key feature of the redesigned survey is the short panel component which is obtained from four visits to the same address over a period of 18 months. We exploit the information in 12 quarters of micro data collected over the period 2000-2002 and study household and individual level attrition within 3, 12 and 15 months of the initial interview. Attrition is a phenomenon which is attributed to demographic and economic factors, including conditions in the labor market. If attrition is systematically related to the labor force status of individuals, this could result in biases in labor market indicators. . Our empirical investigation indeed provides strong evidence that attrition takes this non-ignorable form. The survey protocol allows interviews with substitute households or individuals who arrive at the designated address after the initial round. This practice appears to reduce the distortive influence of attrition. / Bu makale 2000 yılından beri toplanmakta olan “Yeni” Hanehalkı İşgücü Anketindeki kayıpranma örüntülerinin ekonometrik analizini içermektedir. Yeniden kurgulanan anketin temel özelliği aynı adrese 18 aylık bir dönemde dört ziyaret içermesiyle oluşan kısa panel boyutudur. Çalışmada 2000-2002 arasında 12 çeyrekten derlenen mikro veriler kullanılarak, ilk görüşmeden sonraki 3, 12 ve 15 aylık dönemde hane ve birey düzeyinde kayıpranma incelenmektedir. Kayıpranma işgücü pazarında karşılaşılan durumlar da dahil olmak üzere, bir dizi demografik ve ekonomik faktöre bağlanan bir olgudur. Kayıpranmanın bireylerin işgücü durumuyla sistematik bir ilişkisi olması işgücü istatistiklerinde yanlılığına yol açabilir. Nitekim ampirik sorgulamamız göz ardı edilemez bir kayıpranmanın varlığına işaret etmektedir. Anket protokolu adrese ilk ziyaretten sonra gelen hanehalkı ve bireylerle görüşme yapılmasına izin vermektedir. Bulgularımız bu uygulamanın kayıpranmanın yol açtığı yanlılığı bir miktar giderdiğine ilişkin ipuçları içermektedir.Publication Open Access Female labor force participation in Turkey: a synthetic cohort analysis, 1988-2013(2017) Kırdar, Murat Güray; Dayıoğlu, Meltem; Department of Economics; Tunalı, Fehmi İnsan; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 105635We study the aggregate labor force participation behavior of women over a 25-year period in Turkey using a synthetic panel analysis. In our decomposition of age, year, and cohort effects, we use three APC models that have survived the scrutiny of the demography community. We rely on predictions from just-identified models that render different methods comparable. The exercise is carried out by rural/urban status and by education to tease out some key differences in behavior. Our comparative methodology yields remarkably robust age-profiles that represent the behavior of a typical woman over her life-cycle. Notably an M-shape attributable to child-bearing related concerns is detected in rural areas and for low-educated women in urban areas. We also find that later birth-cohorts among the less-educated women—which constitutes the majority of the female workforce—are significantly more likely to participate, which implies that the recent rise in the aggregate participation rates is not only due to rising education levels and that the current substantial gap in participation by education will decrease.Publication Open Access How (not) to integrate blood subtyping technology to kidney exchange(Elsevier, 2018) Department of Economics; Yılmaz, Özgür; Sönmez, Tayfun; Ünver, Utku; Faculty Member; Faculty Member; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 108638; N/A; N/AEven though kidney exchange became an important source of kidney transplants over the last decade with the introduction of market design techniques to organ transplantation, the shortage of kidneys for transplantation is greater than ever. Due to biological disadvantages, patient populations of blood types B/O are disproportionately hurt by this increasing shortage. The disadvantaged blood types are overrepresented among minorities in the US. In order to mitigate the disproportionate harm to these biologically disadvantaged groups, the UNOS reformed in 2014 the US deceased-donor kidney-allocation system, utilizing a technological advance in blood typing. The improved technology allows a certain fraction of blood type A kidneys, referred to as subtype A2 kidneys, to be transplanted to medically qualified patients of blood types B/O. The recent reform prioritizes subtype A2 deceased-donor kidneys for blood type B patients only. When restricted to the deceased-donor allocation system, this is merely a distributional reform with no adverse impact on the overall welfare of the patient population. In this paper we show that the current implementation of the reform has an unintended consequence, and it de facto extends the preferential allocation to kidney exchange as well. Ironically this "spillover" not only reduces the number of living-donor transplants for the overall patient population, but also for the biologically disadvantaged groups who are the intended beneficiaries of the reform. We show that minor variations of the current policy do not suffer from this unintended consequence, and we make two easy-to-implement, welfare-increasing policy recommendations.Publication Metadata only Is there a virtuous cycle between wages and productivity? Turkish experience after the transition to democracy(Elsevier Ltd, 2024) Taymaz, Erol; Voyvoda, Ebru; Department of Economics; Yılmaz, Kamil; Department of Economics; College of Administrative Sciences and EconomicsWe analyze the behavior of plant-level real wages and productivity in Turkish manufacturing after the transition to democracy in 1987 and test for the direction of the causality between these two variables. The Turkish experience is almost an experimental case because successive governments after 1987 let real wages increase rapidly under the pressure of intensifying political competition. Real wages in state-owned enterprises increased by nearly 200% from 1988 to 1993, followed by a 130% increase in real wages in private manufacturing. Our analysis shows that labor and total factor productivity increased at an unprecedented rate during the same period in response to the exogenous wage hikes. Econometric estimates provide strong empirical evidence supporting the hypothesis that there is a bi-directional relationship between wages and productivity, and wage increases do not reduce surplus because the increase in productivity (value added per worker) compensates for increasing wages. © 2023 Elsevier LtdPublication Open Access Kidney exchange: further utilization of donors via listed exchange(Elsevier, 2014) Department of Economics; Yılmaz, Özgür; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 108638There is a set of incompatible patient-donor pairs and these pairs are matched pairwise. A match between two pairs corresponds to a paired kidney donation, where pairs exchange donated kidneys, or a paired listed exchange, where the first donor donates a kidney to the deceased donor wait-list, the first patient receives the kidney of the second donor, and the second patient receives a priority on the wait-list. We characterize the set of exchanges with the maximum number of transplants from the set of pairs. This characterization generalizes the well-known Gallai-Edmonds Decomposition Theorem.Publication Metadata only On the past, present, and future of the Diebold-Yilmaz approach to dynamic network connectedness(Elsevier Science Sa, 2023) Diebold, Francis X.; Department of Economics; Yılmaz, Kamil; Department of Economics; College of Administrative Sciences and EconomicsWe offer retrospective and prospective assessments of the Diebold-Yilmaz connected-ness research program, combined with personal recollections of its development. Its centerpiece in many respects is Diebold and Yilmaz (2014), around which our discussion is organized.Publication Metadata only Price discrimination through multi-level loyalty programs(Springer, 2016) Department of Business Administration; Department of Economics; Sayman, Serdar; Usman, Ali Murat; Faculty Member; Teaching Faculty; Department of Business Administration; Department of Economics; College of Administrative Sciences and Economics; College of Administrative Sciences and Economics; 112222; 100999Loyalty programs often feature multiple rewards with different requirements; for instance, an airline offering a free domestic ticket for 10 K miles, and an international ticket for 20 K miles. This research focuses on the role of multi-level rewards as a segmentation and price discrimination mechanism: Multi-level rewards can increase firm profits when buyers differ in purchase frequency and/or time discount factor. We propose that a program with two rewards can be designed in such a way that (i) it is more profitable than a one-reward program, and (ii) buyers self-select. Light users prefer to receive the smaller reward two times over receiving the larger reward one time, even though the smaller reward is less than half of the larger reward. We show that the smaller reward helps the firm enlarge its base in the light user segment. We also compare multi-level programs with quantity discounts.Publication Open Access School choice under partial fairness(Society for Economic Theory, 2019) Dur, Umut; Gitmez, A. Arda; Department of Economics; Yılmaz, Özgür; Faculty Member; Department of Economics; College of Administrative Sciences and Economics; 108638We generalize the school choice problem by defining a notion of allowable priority violations. In this setting, a weak axiom of stability (partial stability) allows only certain priority violations. We introduce a class of algorithms called the student exchange under partial fairness (SEPF). Each member of this class gives a partially stable matching that is not Pareto dominated by another partially stable matching (i.e., constrained efficient in the class of partially stable matchings). Moreover, any constrained efficient matching that Pareto improves upon a partially stable matching can be obtained via an algorithm within the SEPF class. We characterize the unique algorithm in the SEPF class that satisfies a desirable incentive property. The extension of the model to an environment with weak priorities enables us to provide a characterization result that proves the counterpart of the main result in Erdil and Ergin (2008).