This thesis consists of four papers, of which paper 1 and 4 are co-written with Mikael Bask. Paper [1] implements chartists trading in a sticky-price monetary model for determining the exchange rate. It is demonstrated that chartists cause the exchange rate to "overshoot the overshooting equilibrium" of a sticky-price monetary model. Chartists base their trading on a short-long moving average. The importance of technical trading depends inversely on the time horizon in currency trade. The exchange rate's perfect foresight path near long-run equilibrium is derived and it is demonstrated that the shorter the time horizon, the greater the exchange rate overshooting. The aim of Paper [2] is to see how the dynamics of the basic target zone model changes when chartists and fundamentalists are introduced. Chartists use technical trading and the relative importance of technical and fundamental analyses depend on the time horizon in currency trade. The model also includes realignment expectations, which increase with the weight of chartists. The introduction of chartists may significantly reduce and reverse, the so-called "honeymoon effect" of a fully credible target zone. Further, chartists may cause the correlation between the exchange rate and the instantaneous interest rate differential to become either positive or negative. Using a chartist-fundamentalist set-up, Paper [3] derives the effects on the current exchange rate of central bank intervention. Fundamentalists have rational expectations and chartists use so called support and resistance levels in their trading. This technique results in chartists having both bandwagon expectations and regressive expectations. Chartists may enhance or suppress the effect of intervention depending on their expectations. The results indicate that a chartist channel exists. The aim of Paper [4] is threefold; (i) to investigate if there is a unique rational expectations equilibrium (REE) in a new Keynesian macroeconomic model augmented with technical trading, (ii), to investigate if the unique REE is adaptively learnable and, (iii), to investigate if this unique and adaptively learnable REE is desirable in an inflation rate targeting regime. The monetary authority is using a Taylor rule when setting the interest rate. A main conclusion is that a robust Taylor rule implies that the monetary authority should increase (decrease) the interest rate when the CPI inflation rate increases (decreases) and when the currency gets stronger (weaker).

This dissertation is divided into four essays, each of them having its own structure and methodological framework. Although each of the essays making the chapters of the thesis is self-contained, their topics are very closely related. Consequently, the reader will be able to follow the thesis in its unity. Essay I is a selective survey of the extensive, mostly theoretic, literature dealing with monetary policy rules. We aim at contextualization of the monetary policy rules in the existing monetary economics literature. We explain the logic, the inspiration and the history of the rules for the monetary policy conduct. We distinguish between instrument rules and targeting rules as two basic categories. Finally, we resume specific issues related to policy rules for small open economies. Essay II studies the logic of short-term interest rate setting pursued by 15 EU countries before and after the launch of the EMU. We employ econometric estimation of the augmented Taylor rule (TR) for individual 15 EU countries and the Euro area. Although a vast empirical evidence is available for the major economies like the US, the UK or Germany, there is an important gap in our understanding of the factors behind the short-term interest rate dynamics in smaller economies. We find that in the period preceding the euro adoption, the TR is a poor representation of monetary policy setting in most EU countries and that many central banks considered decisions made by dominant economies rather than their domestic macroeconomic developments. The analysis of monetary policy rule of the ECB features additional problems related to the heterogeneity of the EMU. We argue that results based on Euro-area aggregated series, commonly presented in empirical studies, are subject to diverse econometric problems. We provide some evidence that the ECB is concerned also with national information and propose quasi-panel analysis as a viable framework. Essay III explores the relation between the existing monetary policy and domestic price stability in small open emerging economies, in particular the 12 EU new member states. This work has three principal objectives. First, it aims at revealing the logic of interest rate setting pursued by monetary authority of each country. The linear specification of the Taylor rule, applied already in the Essay II, is accompanied by an extensive analysis of nonlinearities in monetary policy rules and the inference on their possible sources. We find that the official monetary policy is sometimes inconsistent with the empirical evidence on the short term interest rate setting. The second objective consists in revealing the determinants of the inflation process. We have found that inflation rates are driven not only by backward persistency but also by the forward-looking component. Third, we employ analysis of the conditional inflation variance so as to give account on the viability of the existing monetary policy setting for price stability. We conclude that the policy of inflation targeting seems to be preferable to exchange rate peg because it allows decreasing not only inflation rate but also its conditional variance. Essay IV seeks to shed light on inflation dynamics of four CEEC (Czech Republic, Hungary, Poland and Slovakia) and test when the predominant model of inflation, the New Keynesian Philips Curve (NKPC), is consistent with the data of these countries. According to the microfounded NKPC, the current inflation is related to inflation expectations and the real marginal cost. The empirical validity of this model has recently become a subject of major controversy in the monetary economics. Although we find some favorable evidence for the NKPC, it seems to be too restrictive model for small open economies. In particular, the failure of the NKPC to explain the inflation dynamics of these countries may be related to the assumption that inflation is related to forward-looking price setting of domestic monopolist firms while our evidence suggests that prices in CEEC have an important backward-looking component and the inflation is significantly driven by external factors like the exchange rate and the foreign inflation rate.

This thesis presents three papers within the field of dynamic macroeconomics. The first paper, entitled “Medium-frequency cycles and the remarkable near trend-stationarity of output”, presents a dynamic stochastic general equilibrium model with endogenous growth, capable of reconciling the observed large medium-frequency fluctuations in output, with its long run (near) trend-stationarity. This requires a model in which standard business cycle shocks lead to highly persistent movements around trend, without significantly altering the trend itself. The robustness of the trend also requires that scale effects are eliminated both in the long and short runs. In an estimated version of the model, a financial-type shock to the stock of ideas emerges as the key driver of the medium frequency cycle. The second paper, entitled “Learning from learners”, is an intervention into two long running debates: the first, on whether learnability may be used to rule out explosive paths for inflation in New Keynesian models, and the second, into whether Taylor rule parameters may be identified from observing the data. We find that in an economy populated with traditional macroeconomic learners, Taylor rule parameters can always be identified by sophisticated econometric techniques. Furthermore, when all agents in the economy use such sophisticated techniques, stationary sunspot solutions are readily learnable, and there is no guarantee of convergence to a stationary solution even in the “determinate” case. This implies that learnability cannot be used for equilibrium selection. Finally, in the third paper, “Efficient simulation of DSGE models with inequality constraints” (joint with Michael Paetz), we present a new algorithm for the simulation of models subject to inequality constraints, such as the zero lower bound on nominal interest rates. Our algorithm is shown to deliver higher accuracy than all other non-global algorithms, and leading speed. We go on to provide a number of applications of our algorithm.

John B. Taylor, professor i nationalekonomi vid Stanford University, presenterade år 1993 en penningpolitisk regel som syftade till att vara ett hjälpmedel för centralbanker vid räntebeslut. Taylor-regeln är mycket enkel i sitt uförande och baseras på att styrräntan bör sättas efter två variabler: BNP-gapet och inflationsavvikelsen. Denna styrränteregel fick genomslag inom den vetenskapliga världen men spreds även till makroekonomisk praktik och medförde stora förändringar för penningpolitiken. Flera empriska studier har publicerats sedan Taylor-regeln tillkom och det råder det delade meningar om hur väl Taylor-regeln presterar för olika typer av ekonomier och hur användbar den är idag. Det har även uppkomit nya teorier angående trögheten i effekterna av styrränteförändringar och vid vilken tidpunkt dessa får en inverkan på inflationstakten. Syftet med denna uppsats är att jämföra hur väl den ursprungliga Taylor-modellen och en tidslaggad modell förklarar centralbankernas historiska styrräntesättning i fem länder med inflationsmål under tidsperioden 2000-2013. Analysen av resultaten görs med utgångspunkt i ländernas olika ekonomiska egenskaper samt tidsperioden som studien omfattar. Studien begränsas till jämförelser av de två Taylor-modellernas tillämpbarhet vid styrräntesättningar för länderna Brasilien, Kanada, Polen, Sverige och Sydafrika. De två modellerna modifieras också med en styrränteutjämningsfunktion.   Våra resultat tyder på att den ursprungliga Taylor-regeln presterar bättre i förhållande till den tidslaggade modellen när det gäller att förklara den faktiska styrräntesättningen idag för alla länder i studien utom Polen. Den tidslaggade presterar dock bättre än den ursprungliga för de utvecklade ekonomierna Sverige och Kanada under 1990-talet. Båda modellerna gör kraftiga över- och underskattningar som till stor del avhjälps med den utjämningsfunktion som vi tillämpar. Koefficienterna hålls konstanta över hela tidsperioden, vilket inte är rimligt då en viss dynamik bör inkluderas så att regeln justeras efter varje period då för mycket vikt läggs vid BNP-variabeln som såldes är en bidragande faktor till regelns över- och underskattningar. Regeln presterar bättre för ekonomier med stabila förhållanden mellan tillväxttakt och inflationstakt än för länder som lider av mer volatila förhållanden mellan dessa två variabler, likt tillväxtländerna i vår studie. Dessutom ger Taylor-regeln skattningar som ligger närmre den faktiska styrräntesättningen under de tidigare delarna av perioden för att sedan till större del börja avvika från den faktiskt satta styrräntan.   Slutsatserna som kan dras utifrån våra resultat är att den ursprungliga Taylor-regeln presterar bäst i att beskriva ett lands styrräntesättning sett till kvantitativa mått medan en tidslaggad modell tar större hänsyn faktiska förhållanden. Över lag presterar modellerna bättre för de utvecklade ekonomierna än för tillväxtekonomierna och huruvida storleken på ekonomin har någon inverkan är svårt att avgöra. Resultaten tyder också på att Taylor-regeln med tidslagg ligger närmre den faktiska styrräntesättningen för de utvecklade ekonomierna under 1990-talet än under perioden 2000-2013 medan den ursprungliga presterar bättre idag. / John. B Taylor, professor of Economics at Stanford University, presented a monetary policy rule in 1993 which intended to help central banks with their interst rate decisions. In its design the Taylor-rule was very simple and based on only two variables: the GDP-gap and the deviation of actual inflation from the inflation target. The Taylor rule had a great impact on the academic research and also contributed to changes within monetary policy around the world. Many empirical studies have been published on the Taylor rule and there are divided contentions about its applicability in different kind of economies and its relevance today. New theories have also been published regardning the time aspect of the impact on inflation due to a change in the interest rate. The intentions of this study is to make a comparsion between the original Taylor rule and a Taylor rule including a time lag regarding how well they describe the actual interest rates set by the central banks in five countries during the period 2000-2013. The results will be analyzed under consideration of the different economies attributes. The study compares the two kinds of Taylor rules and the applicability in describing the historical interest rate in Brazil, Canada, Poland, Sweden and South Africa. The two rules have also been modified with an interest rate smoothing-function.   Our results conclude that the original Taylor rule describes the historical interest rate better than the rule including a time lag for the time period 2000-2013 for all countries apart from Poland. For the developed economies Canada and Sweden the time lagged model show less deviations for the 1990’s. However both rules tend to over and underestimate the valutation of the interest rate. The smoothing function does to some extent correct this problem. The coefficients of the variables are held constant during the study which in reality should not be the case. They should instead be adjusted between every period to make allowances for the different relationship of the two variables. Mostly too much weight is put on the GDP-variable which should be a contributing cause of the overestimations. The rules do however have the tendency to describe the historical interst rate of the developed economies superior to the developing economies. The performance is greater at the beginning of the period with less deviation from the actual outcome than later on. The conclusion of our study is that the original Taylor rule generally performs superior to the one including time lag with conciderations to the deviations from the actual interest rates. However, the Taylor rule including the time-lag does allow for actual circumstances which the original Taylor rule does not take into consideration. Mainly the rules do perform better for developed economies compared to developing economies. Regarding the impact of the size of the economy on the applicability of the rules it was difficult to conclude anything specific. The Taylor rule with the time-lag is more applicable for the developed economies during the earlier time period, the 1990’s, than the later time period, the 2000’s where the original Taylor rule shows less deviations.