Afsin Sahin

Seasonality in inflation volatility: Evidence from Turkey

This paper assesses the presence of seasonal volatility in price indexes where a similar type of pattern has been reported in asset prices in financial markets. The empirical evidence from Turkey for the monthly period from 1987:01 to 2007:05 suggests the presence of seasonality in the conditional variance of inflation. Thus, inferences for the models that do not account for the seasonality in the conditional variance will be misleading.

A comparison of time series and machine learning models for inflation forecasting: empirical evidence from the USA

This study compares time series and machine learning models for inflation forecasting. Empirical evidence from the USA between 1984 and 2014 suggests that out of sixteen conditions (four different inflation indicators and four different horizons), machine learning models provide more accurate forecasting results in seven conditions and the time series models are better in nine conditions. Moreover, multivariate models give better results in fourteen conditions, and univariate models are better only in two conditions. This study shows that machine learning model prevails against time series models for the core personal consumption expenditure (core-PCE) inflation forecasting, and the time series model (ARDL) is better for the core consumer price (core-CPI) index inflation forecasting in all horizons.

Rethinking Interest Rate Volatility as a Macroprudential Policy Tool

Along with most other central banks, Turkeys central bank has implemented unconventional policies since the 2007/2008 financial crisis. Financial stability has been one of the targets of these macroprudential policies. However, since Turkey is working toward this goal without increasing its inflation rate, tracking only short-term interest rates to measure this policys effectiveness would be inefficient. In this paper, we provide empirical evidence from Turkey that interbank interest rate volatility can be an additional tool for monetary policy makers to help achieve the goal of financial stability. Impulse responses generated from the Vector Autoregressive models indicate that interest rate volatility increases interest rates, depreciates domestic currency and decreases credit growth and output. Its statistically insignificant effect on prices is open to interpretation.

Output–Employment Relationship Across Sectors: A Long‐ Versus Short‐Run Perspective

This paper investigates the nature of the output-employment relationship by using the Turkish quarterly data for the period from 1988 to 2008. Even if we fail to find a long-run relationship between aggregate output and total employment, there are long-run relationships for the aggregate output with non-agricultural employment and sectoral employment levels for seven of nine sectors that we consider. However, a further investigation for the output and employment relationship within a short-run perspective do not reveal statistically significant relationships for either total employment, or non-agriculture employment or the eight out of the nine sectors that we consider. Thus, it seems that sustainable growth is an essential economic agenda for employment generation concerning the sectors and that there is a long-run link but weak short run link with demand.

Effectiveness of the reserve option mechanism as a macroeconomic prudential tool: evidence from Turkey

This article assesses the effectiveness of a novel macroprudential tool – the reserve option mechanism (ROM) – which Turkey’s central bank developed during the post-2008 period and has employed to control the risk associated with excessive capital flows. We assess how capital flows have affected economic variable changes since the introduction and usage of the ROM. Empirical evidence gathered from Turkey suggests that the tool decreases the effect of capital flow on capital flow (positive shock to capital flow dies out faster or becomes less persistent) and diminishes the effects of capital flow shocks on exchange and interest rates.

Staying vigilant of uncertainty to velocity of money: an application for oil-producing countries

Uncertainty in economic and financial variables has substantially changed the dynamics in monetary economics during the last two decades in oil‐producing countries. However, there are types of uncertainties which affect these countries heterogeneously in the short run and long run. For this purpose, Autoregressive Distributed Lag Model (ARDL) is estimated for oil‐producing countries and non‐homogenous results for money supply, income, oil, interest rate, US monetary policy and exchange uncertainties have been obtained.

Examination of relation between nutrient components and fruits: Biplot approach

Adequate intake of fruits and vegetables as part of the daily diet may help prevent major diseases. Low fruit intake is a major risk factor for cancer, coronary heart disease and stroke. The World Health Organization recommends eating at least five portions of a variety of fruit, which is nearly 400 g/day. Essential nutrients, water, carbohydrates, oils and vitamins are needed in appropriate quantities in order to have a well-functioning body. In this study we try to carry out a food composition study to identify and determine the chemical nature of the organic and inorganic macro-nutrient and micro-nutrient properties of the main fruit types that affect human nature, by a biplot graphical approach. The biplot can be considered as multivariate equivalents of scatter plots that have been used for graphically analyzing bivariate data. Biplot approaches show a simultaneous display of fruits and nutrient components in low dimensions. In the present study, the theory of biplot and different types of biplot will be given and than an application of the biplot approach will be applied to the real data.