Title:

Turkish consumption and saving

The principle aim of this thesis is to construct a consumption function for Turkey for policy analysis using the annual State Planning Organisation (SPO) timeseries data. This study commences from 1962 and extends until the end of 1994, when a financial crisis occurred in Turkey. It attempts to analyse not only the decline in the private savings rate during the first half of the 1980s, but also the significant rise from 1986 onwards. The thesis starts with an introduction which explodes the main research objectives, considers the existing consumption theories and extentions, records the main data features to be explained, briefly overviews the modelling strategy and discusses the basic considerations of the research and gives the structure of thesis. A literature survey on the theory of consumption is given in Chapter 2. The LifeCycle/ PermanentIncome hypothesis is considered as central to the two mainstream approach. : the Euler approach and the solvedout approach. These approaches are further extended by considering uncertainty and precautionary saving, credit restrictions, saving and leisure. habit or costs of adjustments and the durability of goods, the role of assets and asset prices. financial liberalisation and demographic factors. Finally, comparisons between the two approaches arc made in the conclusion of that chapter. Theory can deliver concepts with permanent relationships in economics, but it should be supported by empirical findings, since theory alone is insufficient to determine the actual economic relationship. Hence, Chapter 3 focuses on theoretical and appl ied modelling issues to construct a theoryconsistent, congruent and encompassing consumption function. Congruency implies that the empirical model matches the available evidence in al l measured attributes (i.e., it is consistent with the theory from which it was derived, has unexplained components that arc innovations against available information, has basic parameters that are constant, is data admissible, and where any conditioning variables are weakly exogenous for the parameters of interest). Encompassing denotes that the model of interest can account for the result of rival models of the same phenomena. I also define structure as the set of invariant features of the economic mechanism. A parameter can be structural only if it is invariant for an extension of the sample period (constant), is invariant with respect to changes elsewhere in the economy (regime shifts), and is invariant over extensions of the information set (adding more variables). Chapter 4 examines the smallsample properties of the statistical methods used by means of Monte Carlo simulations. The informativeness of the data is investigated in an unrestricted Vector Autoregression (VAR) with smallsamples of noisy data combined with a high real growth rate and nominal inflation. This is to see how the relative drift dominates in explaining the informativeness of the data. The Monte results are summarised by using response surfaces to relate the biases to sample size. The ratio of standard deviations to standard errors in each equation is also analysed. The strong impacts of the system error variances in these response surfaces indicate the importance of high variances in VA Rs. Furthermore, I found noise, and a function of the signal to noise ratio. and crossequation correlation had a large impact, but less effect from the relative drift. Chapter 5 presents an overview of the Turkish Economy, particularly during the sample period. by pointing out the lessons to be drawn from the stabilisation experiments and their effect on the private sector saving decision in Turkey. The aim of Chapter 6 is to get nominal housing wealth and housing price data from the available data, such as the nominal private disposable income. nominal private investment in the housing sector and the consumer price index, since housing wealth is claimed to be a major determinant of private savings in Turkey. Chapter 7 aims to reveal the problems of Turkish data by analysing the history of the Turkish a1ional Accounts to construct a database for estimating a consumption function for Turkey. GDP by expenditure is constructed from five different sources. Turkish accounting residuals are allocated by applying the linear regression approach. The results show that GDPbyoutput is more reliable than the GDPbyexpenditure measure for Turkey. Chapter 8 is devoted to the time series modelling and evidence. Previous findings on consumption for Turkey have been formulated using conventional econometric techniques with a static estimation methodology within the Permanent Income Hypothesis (PIH). I adopted the equilibrium correction model (ECM) solvedout consumption function approach and tried to incorporate the effects of age. precautionary behaviour in the case of uncertainty, credit constraints, habits or costs of adjustments. and the durability of goods for developing belier understanding of private sector savings behaviour in Turkey. The modelling is based on the dynamic econometric methodology that involves the estimation of a general unrestricted model (GUM). a cointegration and longrun analysis, and the simplification of the GUM to a parsimonious dynamic model that is deduced by applying a sequential testing procedure. The final model is congruent: It matches the available evidence in all measured attributes and forecasts well, has white noise errors and constant parameters, and encompasses the VAR model equation as well as other specifications in previous models. Moreover, the model has a structural interpretation. The results of the final model reveal strong positive effects of the real interest rate. inflation and inflation uncertainty, a strong negative effect of population aged 1544, a positive effect after one lag period of the change in the average propensity to consume. which represents the effects of expectations, habits or adjustment costs, in addition to the significant effect of the inverse of per capita Private Disposable Income and the change in housing wealth to income ra1io on the private average propensity to consume in Turkey. These findings offer an explana1ion for the salient features of the Turkish consumption pattern observed from 1he lime series data. These results also provide some policy implications such that inOation control should be strengthened and improved for consumption stabilisation. Furthermore. interest rate policy also has an important role to play in the savings process in Turkey. The research on smallsample properties of 1hc statistical methods by means of Monte Carlo Simulations strengthens the results of the empirical model. These. confirm the poor determination of intercepts in I(I) VARs, and the corresponding advantages of an equilibrium correction model formulation. Furthermore. the insignificance the of irrelevant dynamics should encourage model builders to use a dynamic econometric methodology to develop parsimonious models, such as used for building a consumption model for Turkey in this thesis.
