Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
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Article Citation - WoS: 1Citation - Scopus: 1Model Selection Uncertainties and Model Averaging in Autoregressive Time Series Models(Isoss Publ, 2012) Islam, M. Qamarul; Yazıcı, Mehmet; Yazici, Mehmet; Islam, M.Qamarul; Qamarul Islam, M.; İktisatSelecting the correct lag order is necessary in order to avoid model specification errors in autoregressive (AR) time series models. Here we explore the problem of lag order selection in such models. This study provides an in-depth but easy understanding of the model selection mechanism to the practitioners in various fields of applied research. Several interesting findings are reported and through these the pitfalls of the model selection procedures are exposed. In particular, we show that the whole exercise of model selection and subsequent statistical inference invariably depends upon unknown entities, namely the true values of parameters in the model. The model averaging technique is proposed as an alternative to the common practice of model selection and it is shown that, as a result, the properties of post-model-selection estimates substantially improve.Article Citation - WoS: 2Citation - Scopus: 2Job Flow Patterns and Productivity Dynamics in Turkish Manufacturing(World Scientific Publ Co Pte Ltd, 2024) Dogan, Ergun; Islam, M. Qamarul; Yazici, MehmetIn this paper, we analyze the job creation and destruction process, and the productivity dynamics in Turkish manufacturing by size, export status, import status and ownership by using a comprehensive firm-level dataset for the period of 2010-2015. Our focus is on the effect of turnover, which is due to the entry and exit of firms, on both job flows and industrial productivity growth. Our results show that while small firms contribute most to job creation, it is the large firms that contribute most to productivity growth. Regarding ownership, domestic private firms perform better than foreign firms in both job creation and productivity growth. With respect to export status, even though non-exporters outperform exporters in job creation, exporters dominate the productivity growth. As for import status, in job creation, like in the case of export status, non-importers do better but in productivity growth, unlike in the export status, no group of firms dominate, more specifically importers' and non-importers' contributions are close to each other. Another interesting finding is that, turnover effect on industry productivity is positive but very low. The role of incumbent firms in generating productivity growth is much higher than that of entering and exiting firms.Article Citation - WoS: 2Citation - Scopus: 1Impact of Exchange Rate and Customs Union on Trade Balance at Commodity Level of Turkey With Eu (15)(Routledge Journals, Taylor & Francis Ltd, 2011) Islam, M. Qamarul; Yazici, Mehmet; Qamarul Islam, M.This paper investigates the short-run and long-run impact of exchange rate and customs union on the trade balance at commodity-group level of Turkey with EU (15). Bounds testing approach is employed where a new strategy in the model selection phase is odopted ensuring that optimal model is selected from those models satisfying both diagnostics and cointegration. Results indicate that in the short-run exchange rate matters in determination of trade balance of 13 commodity groups out of 21 and customs union in 8 cases. Pattern of response of trade balance to exchange rate does not suggest a J-curve effect in any of cases. As for the long-run effect, neither exchange rate nor customs union has a statistically significant effect on trade balance of any of commodity groups, suggesting that those significant short-run effects don't last into long-run.Article Citation - WoS: 4Citation - Scopus: 5Is There a J-Curve Effect in Turkish Services(Springer, 2010) Yazici, MehmetThis paper explores the existence of the J-curve effect in Turkish services. The model of Bahmani-Oskooee (Rev Econ Stat 67:500-504, 1985), one of the most commonly employed model in the j-curve literature, is adopted. Using quarterly data from 1986: I to 1998: III, we find that, as a result of real depreciation of Turkish currency, YTL, services trade balance initially improves, then worsens and improves again in the short run. This is a pattern indicating that J-curve effect does not exist in Turkish services sector. We also find that depreciation of Turkish Lira improves the trade balance of the sector in the long run, a result consistent with earlier findings for the whole Turkish economy.Article Citation - Scopus: 1Real Exchange Rates and Job Flows: Evidence From Turkey(Routledge Journals, Taylor & Francis Ltd, 2018) Islam, M. Qamarul; Yazici, Mehmet; Dogan, ErgunThis study investigates the effects of the real exchange rate on job flows in Turkish manufacturing industries between 2006 and 2015 using data at the four-digit NACE Revision 2 level. Using dynamic panel data models, we find that a real appreciation increases gross and net job creation rates, and that the effect of appreciation is magnified as the exposure to international competitiveness of industries increases. We think that this is because Turkish manufacturing firms import a greater share of their inputs compared to the firms in developed countries. Hence, an appreciation creates more jobs because lower imported input costs enable firms to outcompete foreign producers.Article Citation - WoS: 8Citation - Scopus: 11Firm Size and Job Creation: Evidence From Turkey(Routledge Journals, Taylor & Francis Ltd, 2017) Islam, M. Qamarul; Yazici, Mehmet; Dogan, ErgunThis study examines the relationship between firm size and job creation by using an extensive data set covering all non-farm Turkish businesses with 20 or more employees from 2003 to 2010. We find that small firms (firms with employees between 20 and 100 employees) have higher mean job flow rates (job creation, job destruction and net job creation rates) than large firms. Firm size and job flow rates are inversely related, and this relationship is especially prominent for firms with 50 employees or more. Although the overall pattern observed is also observed in both sectors, job creation rates in services are higher than the ones in manufacturing. The magnitudes of job destruction rates are comparable across sectors. Higher job creation rate in services but comparable job destruction rate results in higher net job creation rate in services. As for shares, only for smaller firms (20-49 and 50-99 size categories), job creation shares are greater than their shares in employment. But these firms have disproportionate job destruction shares as well. We also find that only the 20-49 category firms contribute to net job creation more than their share in employment. The smaller firms have high disproportionate shares in job creation and destruction in manufacturing and services as well.Article Citation - WoS: 4Citation - Scopus: 4Inference in Multivariate Linear Regression Models With Elliptically Distributed Errors(Taylor & Francis Ltd, 2014) Yazici, Mehmet; Islam, M. Qamarul; Yildirim, FetihIn this study we investigate the problem of estimation and testing of hypotheses in multivariate linear regression models when the errors involved are assumed to be non-normally distributed. We consider the class of heavy-tailed distributions for this purpose. Although our method is applicable for any distribution in this class, we take the multivariate t-distribution for illustration. This distribution has applications in many fields of applied research such as Economics, Business, and Finance. For estimation purpose, we use the modified maximum likelihood method in order to get the so-called modified maximum likelihood estimates that are obtained in a closed form. We show that these estimates are substantially more efficient than least-square estimates. They are also found to be robust to reasonable deviations from the assumed distribution and also many data anomalies such as the presence of outliers in the sample, etc. We further provide test statistics for testing the relevant hypothesis regarding the regression coefficients.Article Citation - WoS: 13Citation - Scopus: 15Import-Content of Exports and J-Curve Effect(Routledge Journals, Taylor & Francis Ltd, 2010) Yazici, Mehmet; Klasra, Mushtaq AhmadThis article investigates how the response to devaluation of trade balance is affected, compared to J-curve hypothesis, by the presence of imported inputs in the production of exports. Using first the Almon lag technique and then the cointegration and the generalized impulse response function analysis, the J-curve effect is examined in two sectors of Turkish economy (manufacturing and mining), which use imported inputs at different rates. Based on the data covering the period from the first quarter of 1986 to the third quarter of 1998, our results indicate that in neither sector J-curve exists and that the violation of the J-curve effect is more severe in the sector with higher import content.Article Citation - WoS: 4Citation - Scopus: 10The Exchange Rate and the Trade Balances of Turkish Agriculture, Manufacturing and Mining(Springer, 2008) Yazici, MehmetThis paper investigates and compares the response to the exchange rate changes of trade balances of three Turkish sectors; agriculture, manufacturing and mining. The impact on trade balance of exchange rate changes is examined using the trade balance model employed in Bahmani-Oskooee [1985, Review of Economics and Statistics 67: 500]. Analysis is conducted based on the quarterly data from 1986: I to 1998: III. It is observed that in response to domestic currency depreciation trade balance of each of all three sectors first improves, then deteriorates and then improves again. Despite exhibiting similar pattern of reaction to the exchange rate change in the short run, long-run or overall response of trade balance differs across the sectors; while trade balances of both manufacturing and mining improve in the long run, agricultural trade balance worsens as a result of domestic-currency depreciation.