Ekonomi Bölümü Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1936
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Article Citation - WoS: 1Citation - Scopus: 1Understanding Covid-19 Mobility Through Human Capital: a Unified Causal Framework(Springer, 2023-02-21) Bilgel, Fırat; Karahasan, Burhan CanThis paper seeks to identify the causal impact of educational human capital on social distancing behavior at workplace in Turkey using district-level data for the period of April 2020 - February 2021. We adopt a unified causal framework, predicated on domain knowledge, theory-justified constraints anda data-driven causal structure discovery using causal graphs. We answer our causal query by employing machine learning prediction algorithms; instrumental variables in the presence of latent confounding and Heckman's model in the presence of selection bias. Results show that educated regions are able to distance-work and educational human capital is a key factor in reducing workplace mobility, possibly through its impact on employment. This pattern leads to higher workplace mobility for less educated regions and translates into higher Covid-19 infection rates. The future of the pandemic lies in less educated segments of developing countries and calls for public health action to decrease its unequal and pervasive impact.Article Citation - WoS: 1Citation - Scopus: 1Great Recession and News Shocks: Evidence Based on an Estimated Dsge Model(Springer, 2021-05-21) Nebioğlu, DenizThis paper examines whether productivity news shocks were among the drivers of the Great Recession. To do this, the Smets and Wouters (Am Econ Rev 97(3):586–606, 2007. https://doi.org/10.1257/aer.97.3.586) model is extended by a generalized preference specification which allows for scaling wealth effects on the labor supply. The resulting model is estimated using Bayesian methods which draw upon the US data from the period 1965Q2 to 2014Q3. There are four main results: (i) Estimation of the model is inconclusive regarding the degree of wealth elasticity of the labor supply. As a result, two complementary versions of the model prevail, each of which has differing implications for the transmission and the quantitative importance of exogenous shocks. (ii) When the degree of wealth elasticity of the labor supply is low, news shocks replace risk premium shocks, suggesting that news shocks are one possible reason for fluctuations in US business cycles. (iii) When the Great Recession period is analyzed through the lenses of the two complementary versions of the model, two explanations emerge as potential reasons behind the deepening of the crisis: worsening credit conditions as well as the collapse of over-optimistic expectations regarding future productivity. (iv) For both model specifications, general developments in productivity are estimated to be positive. Therefore, productivity slowdown is not considered to be among the reasons for the emergence or persistence of the Great Recession.Article Citation - WoS: 8Citation - Scopus: 11Hematocrit Levels and Thrombotic Events in Patients With Polycythemia Vera: an Analysis of Veterans Health Administration Data(Springer, 2019-09-24) Parasuraman, Shreekant; Robyn Scherber; Jingbo Yu; Li Wang; Dilan Paranagama; Sulena Shrestha; Başer, Onur; Yu, Jingbo; Paranagama, Dilan; Shrestha, Sulena; Scherber, Robyn; Wang, LiPatients with polycythemia vera (PV) have a high incidence of thrombotic events (TEs), contributing to a greater mortality risk than the general population. The relationship between hematocrit (HCT) levels and TE occurrence among patients with PV from the Veterans Health Administration (VHA) was evaluated to replicate findings of the CYTO-PV trial with a real-world patient population. This retrospective study used VHA medical record and claims data from the first claim with a PV diagnosis (index) until death, disenrollment, or end of study, collected between October 1, 2005, and September 30, 2012. Patients were aged ? 18 years at index, had ? 2 claims for PV (ICD-9-CM code, 238.4) ? 30 days apart during the identification period, continuous health plan enrollment from 12 months pre-index until end of study, and ? 3 HCT measurements per year during follow-up. This analysis focused on patients with no pre-index TE, and with all HCT values either < 45% or ? 45% during the follow-up period. The difference in TE risk between HCT groups was assessed using unadjusted Cox regression models based on time to first TE. Patients (N = 213) were mean (SD) age 68.9 (11.5) years, 98.6% male, and 61.5% white. TE rates for patients with HCT values < 45% versus ? 45% were 40.3% and 54.2%, respectively. Among patients with ? 1 HCT before TE, TE risk hazard ratio was 1.61 (95% CI, 1.03–2.51; P = 0.036). This analysis of the VHA population further supports effective monitoring and control of HCT levels < 45% to reduce TE risk in patients with PV.Article Citation - WoS: 17Citation - Scopus: 19Oil Prices and Economic Activity in Brics and G7 Countries(Springer, 2019-08-29) Kılıç, Erdem; Çankaya, SerkanThe effect of oil prices on countries’ economic activity has been the center of attention for decades. The empirical link between oil prices and economic activity has been steadily investigated during this time period but the measured outcomes have revealed mixed results and been inconsistent. This study examines the effect of oil prices on economic activity for Brazil, Russia, India, China, and South Africa (BRICS) and Group of Seven (G7) countries in both short-run and long-run relationships by estimating a maximum likelihood structural vector autoregression model. The model shows that a positive shock to oil prices tends to affect the monetary aggregate in Brazil, Canada, France, Germany, and Russia. The effect on interest rate spread is most significant in India and Russia. Impulse response functions display almost no effect on the gross domestic product in the US and China. A positive response on the consumer price index is observed mostly for developed countries. The response of real exchange rate reveals a positive effect on all countries in varying degrees, with the exception of the US and South Africa. Finally, Granger causality tests were conducted with proper allowance for the non-stationarity of the data. The findings illustrate that the Russian economy is among the economies that are most significantly affected by oil price fluctuations for almost all the selected variables. The models also reveal that the effect of oil price shocks on the US’s and China’s economic activities is only limited to the effect on real exchange rates. Other variables show no or limited reactions to oil prices. We also used the Markov switching maximum likelihood vector autoregression models, which reveals similar results.Article Citation - WoS: 5Citation - Scopus: 3Exports, Real Exchange Rates and Dollarization: Empirical Evidence From Turkish Manufacturing Firms(Springer, 2019-07-15) Karamollaoğlu, Nazlı; Yalçın, CihanWe attempt to uncover the relationship between the real exchange rates and exports shares of manufacturing firms in Turkey by taking into account FX exposures and various firm characteristics. We use a large panel of manufacturing firms to carry out an empirical analysis for the period 2002–2010. Contrary to macro-evidence, firm-level empirical evidence suggests that a depreciation of the Turkish lira seems to favor the external competitiveness of firms in general. We document that a real depreciation of the Turkish lira has a positive impact on export shares and its impact is muted to some extent for firms operating in sectors that use imported inputs intensively. In addition, we estimate that export shares increase as a result of real depreciation for firms having low (naturally hedged) and moderate FX debt-to-export ratios. We do not confirm a strong balance sheet channel where a depreciation of the currency may harm firms’ export performance due to currency mismatch. On the contrary, FX borrowing is estimated to support export performance probably due to undermining finance constraints.Article Citation - WoS: 30Citation - Scopus: 29Out-Of Inr Values and Outcomes Among New Warfarin Patients With Non-Valvular Atrial Fibrillation(Springer, 2014-11-27) Schein, Jeffrey R; Wang, Li; Damaraju, Chandrasekharrao, V; Nelson, Winnie W; Başer, OnurBackground Although efficacious in stroke prevention in non-valvular atrial fibrillation, many warfarin patients are sub-optimally managed. Objective To evaluate the association of international normalized ratio control and clinical outcomes among new warfarin patients with non-valvular atrial fibrillation. Setting Adult non-valvular atrial fibrillation patients (a parts per thousand yen18 years) initiating warfarin treatment were selected from the US Veterans Health Administration dataset between 10/2007 and 9/2012. Method Valid international normalized ratio values were examined from the warfarin initiation date through the earlier of the first clinical outcome, end of warfarin exposure or death. Each patient contributed multiple in-range and out-of-range time periods. Main outcome measure The relative risk ratios of clinical outcomes associated with international normalized ratio control were estimated. Results 34,346 patients were included for analysis. During the warfarin exposure period, the incidence of events per 100 person-years was highest when patients had international normalized ratio < 2:13.66 for acute coronary syndrome; 10.30 for ischemic stroke; 2.93 for transient ischemic attack; 1.81 for systemic embolism; and 4.55 for major bleeding. Poisson regression confirmed that during periods with international normalized ratio < 2, patients were at increased risk of developing acute coronary syndrome (relative risk ratio: 7.9; 95 % confidence interval 6.9-9.1), ischemic stroke (relative risk ratio: 7.6; 95 % confidence interval 6.5-8.9), transient ischemic attack (relative risk ratio: 8.2; 95 % confidence interval 6.1-11.2), systemic embolism (relative risk ratio: 6.3; 95 % confidence interval 4.4-8.9) and major bleeding (relative risk ratio: 2.6; 95 % confidence interval 2.2-3.0). During time periods with international normalized ratio > 3, patients had significantly increased risk of major bleeding (relative risk ratio: 1.5; 95 % confidence interval 1.2-2.0). Conclusion In a Veterans Health Administration non-valvular atrial fibrillation population, exposure to out-of-range international normalized ratio values was associated with significantly increased risk of adverse clinical outcomes.