nÃo hà / A grande importÃncia que alguns estudos internacionais dÃo quanto aos efeitos da volatilidade do cÃmbio e da dinÃmica das polÃticas cambiais sobre as transaÃÃes comerciais vÃm crescendo nos Ãltimos anos. Todavia, nÃo hà um consenso na literatura precedente a respeito dos impactos da volatilidade cambial sobre o fluxo de exportaÃÃes e importaÃÃes. De Grauwe & Skudenly (2000), Ozturk (2006), Bahmani-Oskooee & Hegerty (2007) e Auboin & Ruta (2012) argumentam que uma maior variabilidade da taxa de cÃmbio à prejudicial ao comÃrcio entre paÃses. Para os autores, esse impacto negativo da volatilidade cambial sobre o volume financeiro de comÃrcio internacional decorre da teoria da escolha sob incerteza. O documento concentra-se principalmente em investigar os impactos da volatilidade da taxa de cÃmbio sobre os fluxos de exportaÃÃes de commodities do Brasil para Argentina, Alemanha, China e EUA durante 2000:T1 e 2013:T3. Para verificar a existÃncia de quebras estruturais na funÃÃo tendÃncia das variÃveis reais do modelo de fluxo de comÃrcio bilateral brasileiro, aplicou-se o teste sugerido por Perron & Yabu (2009). Os resultados desse teste indicaram que das vinte e cinco (25) sÃries analisadas, 64% apresentaram uma quebra no nÃvel e inclinaÃÃo na funÃÃo tendÃncia das mesmas. Com o objetivo de evitar resultados viesados em relaÃÃo à ordem de integraÃÃo das sÃries por causa da presenÃa de quebras estruturais, foram aplicados os testes de raiz unitÃria com quebras estruturais desenvolvidos por Lee & Strazicich (2003) e Lee & Strazicich (2004). Os resultados dos dois testes indicaram que das vinte e cinco (25) sÃries analisadas, 80% e 84%, sÃo estacionÃrias com uma e duas quebras, respectivamente. Isto Ã, podem ser caracterizadas como pertencentes à classe I(0). Para finalizar a anÃlise, aplicou-se o teste de quebra estrutural de Bai e Perron (1998) para analisar as mudanÃas na conduÃÃo da polÃtica cambial brasileira durante o perÃodo de 2000 a 2013. Os resultados indicaram a existÃncia de duas (2) quebras estruturais nos parÃmetros estimados da funÃÃo tendÃncia para as exportaÃÃes de commodities. / The great importance that some international studies give about the effects of exchange rate volatility and the dynamics of exchange rate policies on trade transactions have been growing in recent years. However, there is no consensus in the previous literature regarding the impact of exchange rate volatility on the flow of exports and imports. De Grauwe & Skudenly (2000), Ozturk (2006), Bahmani-Oskooee & Hegerty (2007) and Auboin & Ruta (2012) argue that greater variability of the exchange rate is detrimental to trade between countries. For the authors, this negative impact of exchange rate volatility on the financial volume of international trade stems from the theory of choice under uncertainty. The document focuses primarily on investigating the impact of the volatility of the exchange rate on the pattern of commodity exports from Brazil to Argentina, Germany, China and the United States during 2000: T1 and 2013: T3. To verify the existence of structural breaks in the trend function of real variables of the Brazilian bilateral trade flow model, was applied to the test suggested by Perron & Yabu (2009). The results of this test indicated that the twenty-five (25) series analyzed, 64% had a drop in the level and slope of the trend function thereof. In order to avoid biased results in relation to the order of integration of the series because of the presence of structural breaks, unit root tests were applied with structural breaks developed by Lee & Strazicich (2003) and Lee & Strazicich (2004). The results of both tests indicated that the twenty-five (25) series analyzed, 80% and 84%, are stationary with one or two breaks, respectively. That is, they can be characterized as belonging to class I (0). To complete the analysis, we applied the structural break test Bai and Perron (1998) to analyze the changes in the conduct of the Brazilian exchange rate policy during the period 2000 to 2013. The results indicated the existence of two (2) structural breaks the estimated parameters of the trend function for commodity exports.

Ao recuperar dados da década de 60 ao momento atual, o estudo acompanha a evolução do investimento no setor sob diferentes arranjos institucionais. A análise é circunscrita aos segmentos rodoviário, ferroviário, energia elétrica e telecomunicações. As séries são submetidas a testes econométricos propostos em Bai e Perron (1998, 2003b) que, em última instância, procuram identificar eventuais quebras estruturais, associando-as às mudanças institucionais. As quebras encontradas demarcam o ápice e o esgotamento do padrão anterior de organização do setor. Apenas no segmento de telecomunicações é encontrada quebra relacionada ao novo arranjo setorial. Além de acompanhar a evolução dos segmentos abordados, o trabalho apresenta base conceitual para fundamentar a análise dos fenômenos ocorridos nos últimos anos. / This work follows the investment evolution in the infrastructure sector since the 60s. The investigated series are subjected to econometric tests proposed by Bai and Perron (1998, 2003b) that, ultimately, seek to identify possible structural breaks and try to link them to institutional changes. The follow segments were: road, rail, electric power and telecommunications. The tests found breaks related to the peak and the collapse of the former arrangement reforms, respectively in mid-70s and in late 80s. The only break associated with recent changes was found in the telecommunications segment. Additionally, this work presents conceptual basis to support the analysis of the recent developments in the infrastructure sector.

This thesis is comprised of three independent essays. One essay is in the field of macroeconomics and the other two are in time-series econometrics. The first essay, "Productivity and Business Investment over the Business Cycle", is co-authored with my co-supervisor Hashmat Khan. This essay documents a new stylized fact: the correlation between labour productivity and real business investment in the U.S. data switching from 0.54 to -0.1 in 1990. With the assistance of a bivariate VAR, we find that the response of investment to identified technology shocks has changed signs from positive to negative across two sub-periods: ranging from the time of the post-WWII era to the end of 1980s and from 1990 onwards, whereas the response to non-technology shocks has remained relatively unchanged. Also, the volatility of technology shocks declined less relative to the non-technology shocks. This raises the question of whether relatively more volatile technology shocks and the negative response of investment can together account for the decreased correlation. To answer this question, we consider a canonical DSGE model and simulate data under a variety of assumptions about the parameters representing structural features and volatility of shocks. The second and third essays are in time series econometrics and solely authored by myself. The second essay, however, focuses on the impact of ignoring structural breaks in the conditional volatility parameters on time-varying volatility parameters. The focal point of the third essay is on empirical relevance of structural breaks in time-varying volatility models and the forecasting gains of accommodating structural breaks in the unconditional variance. There are several ways in modeling time-varying volatility. One way is to use the autoregressive conditional heteroskedasticity (ARCH)/generalized ARCH (GARCH) class first introduced by Engle (1982) and Bollerslev (1986). One prominent model is Bollerslev (1986) GARCH model in which the conditional volatility is updated by its own residuals and its lags. This class of models is popular amongst practitioners in finance because they are able to capture stylized facts about asset returns such as fat tails and volatility clustering (Engle and Patton, 2001; Zivot, 2009) and require maximum likelihood methods for estimation. They also perform well in forecasting volatility. For example, Hansen and Lunde (2005) find that it is difficult to beat a simple GARCH(1,1) model in forecasting exchange rate volatility. Another way of modeling time-varying volatility is to use the class of stochastic volatility (SV) models including Taylor's (1986) autoregressive stochastic volatility (ARSV) model. With SV models, the conditional volatility is updated only by its own lags and increasingly used in macroeconomic modeling (i.e.Justiniano and Primiceri (2010)). Fernandez-Villaverde and Rubio-Ramirez (2010) claim that the stochastic volatility model fits better than the GARCH model and is easier to incorporate into DSGE models. However, Creal et al. (2013) recently introduced a new class of models called the generalized autoregressive score (GAS) models. With the GAS volatility framework, the conditional variance is updated by the scaled score of the model's density function instead of the squared residuals. According to Creal et al. (2013), GAS models are advantageous to use because updating the conditional variance using the score of the log-density instead of the second moments can improve a model's fit to data. They are also found to be less sensitive to other forms of misspecification such as outliers. As mentioned by Maddala and Kim (1998), structural breaks are considered to be one form of outliers. This raises the question about whether GAS volatility models are less sensitive to parameter non-constancy. This issue of ignoring structural breaks in the volatility parameters is important because neglecting breaks can cause the conditional variance to exhibit unit root behaviour in which the unconditional variance is undefined, implying that any shock to the variance will not gradually decline (Lamoureux and Lastrapes, 1990). The impact of ignoring parameter non-constancy is found in GARCH literature (see Lamoureux and Lastrapes, 1990; Hillebrand, 2005) and in SV literature (Psaradakis and Tzavalis, 1999; Kramer and Messow, 2012) in which the estimated persistence parameter overestimates its true value and approaches one. However, it has never been addressed in GAS literature until now. The second essay uses a simple Monte-Carlo simulation study to examine the impact of neglecting parameter non-constancy on the estimated persistence parameter of several GAS and non-GAS models of volatility. Five different volatility models are examined. Of these models, three --the GARCH(1,1), t-GAS(1,1), and Beta-t-EGARCH(1,1) models -- are GAS models, while the other two -- the t-GARCH(1,1) and EGARCH(1,1) models -- are not. Following Hillebrand (2005) who studied only the GARCH model, this essay examines the extent of how biased the estimated persistence parameter are by assessing impact of ignoring breaks on the mean value of the estimated persistence parameter. The impact of neglecting parameter non-constancy on the empirical sampling distributions and coverage probabilities for the estimated persistence parameters are also studied in this essay. For the latter, studying the effect on the coverage probabilities is important because a decrease in coverage probabilities is associated with an increase in Type I error. This study has implications for forecasting. If the size of an ignored break in parameters is small, then there may not be any gains in using forecast methods that accommodate breaks. Empirical evidence suggests that structural breaks are present in data on macro-financial variables such as oil prices and exchange rates. The potentially serious consequences of ignoring a break in GARCH parameters motivated Rapach and Strauss (2008) and Arouri et al. (2012) to study the empirical relevance of structural breaks in the context of GARCH models. However, the literature does not address the empirical relevance of structural breaks in the context of GAS models. The third and final essay contributes to this literature by extending Rapach and Strauss (2008) to include the t-GAS model and by comparing its performance to that of two non-GAS models, the t-GARCH and SV models. The empirical relevance of structural breaks in the models of volatility is assessed using a formal test by Dufour and Torres (1998) to determine how much the estimated parameters change over sub-periods. The in-sample performance of all the models is analyzed using both the weekly USD trade-weighted index between January 1973 and October 2016 and spot oil prices based on West Texas Intermediate between January 1986 and October 2016. The full sample is split into smaller subsamples by break dates chosen based on historical events and policy changes rather than formal tests. This is because commonly-used tests such as CUSUM suffer from low power (Smith, 2008; Xu, 2013). For each sub-period, all models are estimated using either oil or USD returns. The confidence intervals are constructed for the constant of the conditional parameter and the score parameter (or ARCH parameter in GARCH and t-GARCH models). Then Dufour and Torres's union-intersection test is applied to these confidence intervals to determine how much the estimated parameter change over sub-periods. If there is a set of values that intersects the confidence intervals of all sub-periods, then one can conclude that the parameters do not change that much. The out-of-sample performance of all time-varying volatility models are also assessed in the ability to forecast the mean and variance of oil and USD returns. Through this analysis, this essay also addresses whether using models that accommodate structural breaks in the unconditional variance of both GAS and non-GAS models will improve forecasts.

Vilken effekt har skattetillägg på självrättelser av inkomstdeklarationer för individers benägenhet att begå skattebrott? Enligt grundteorin inom 'economics of crime' bör benägenheten att begå skattebrott minska för en rationell individ av en ökad sannolikhet och kostnad att bli straffad. Studien är en tidsseriestudie som undersöker beteendeförändringar av individers självrättelser av sina inkomstdeklarationer i samband med införandet av skattetillägg som tillkom av Skatteförfarandelagens (2011:1244) reform år 2018. Studien finner statistiskt signifikanta 'structural breaks' år 2019 (med hänsyn till 'first lag') vilket indikerar på ett förändrat beteendemönster i samband med införandet av skattetillägget. Andra faktorer kan dock inte uteslutas.

This paper analyzes how the COVID-19 pandemic has affected the Swedish housing market, and in particular prices and shifts in trends. Different classes of housing objects in various counties are investigated. Combining web scraped housing data for the entirety of Sweden between 2016-01-01 and 2021-03-31, including economic, demographic, socioeconomic and locational data, a hedonic regression model is used to estimate how different variables influence the housing price. The base model is subsequently used to investigate if statistically significant structural breaks exist in relation to the COVID-19 pandemic for the different object types in the entire Swedish market and in certain specific counties. Structural breaks are found for the housing object types ‘Fritidshus’, ‘Lägenhet’ and ‘Radhus’ in the entire Swedish market and for “Villa” in Stockholm county shortly after the pandemic outbreak, suggesting there is evidence for a pandemic infused shift in housing price regime on the Swedish housing market for these object types in stated areas. Splitting the hedonic regression model into three, one pooled regression, one before and one after the identified breaks, and comparing the shifts in impact of the housing price determinants suggests different pandemic effects on different object types. The result indicates that for the object types ‘Lägenhet’ in the entire country and for ‘Villa’ in Stockholm county, living area has an increased impact on the price while the locational variable population density has a decreased impact after the breakpoint date compared to before. This could suggest that for permanent housing objects in these regions, living area might have become increasingly valued over location during the pandemic. The results further indicate the direct opposite effect on the shifted impact in living area and the population density for the price of the temporary housing type Fritidshus in entire Sweden. However, an indication for increased impact of the areas socioeconomic level is noted for all these three object types. These results hold as a ground for further research in the subject.

We provide a flexible means of estimating time-varying parameter models in a Bayesian framework. By specifying the state innovations to be characterized trough a threshold process that is driven by the absolute size of parameter changes, our model detects at each point in time whether a given regression coefficient is con stant or time-varying. Moreover, our framework accounts for model uncertainty in a data-based fashion through Bayesian shrinkage priors on the initial values of the states. In a simulation, we show that our model reliably identifies regime shifts in cases where the data generating processes display high, moderate, and low numbers of movements in the regression parameters. Finally, we illustrate the merits of our approach by means of two applications. In the first application we forecast the US equity premium and in the second application we investigate the macroeconomic effects of a US monetary policy shock. / Series: Research Report Series / Department of Statistics and Mathematics

This paper summarises a series of Asia-Pacific based studies that explore three distinct central and commercial banking regimes, looking at interest rate pricing and transmission. This research is significant for several reasons: (a) the relative lack of research into pricing behaviour and price transmission in Asia-Pacific, (b) the development of new tools to analyse non linear cointegration and hence price asymmetry, (c) economic and financial convergence is now a topic of regional importance, (d) transmission and price behaviour evidence has not been documented in the context of the different central bank policy signaling regimes evident in the region, (e) the banking markets in the region are clearly in the midst of a consolidation and globalisation phase. This follows rapidly from the 1997/98 financial-crisis, (f) there is little evidence in the region of how advances in risk management practice have impacted the price behaviour of the banking industry. A number of findings have been documented. Regional financial integration appears already under way, evidenced by both regional banking mergers and regional consistency in the timing of structural breaks during the Asian crisis. Transmission of policy rates to wholesale rates appears rapid in the case of Hong Kong (HK) and New Zealand (NZ), but slow in the case of Singapore with its currency-basket regime. Generally, there is little evidence of asymmetric interest rate pricing practices in Singapore and HK, whilst asymmetry noted for NZ appears to be largely a function of how banks reacted in a significant decline in rates over a long period prior to the implementation of the Official Cash Rate. / Professional Doctorate

The focus of this paper is to evaluate if forecast produced by the Central Bank of Sweden (Riksbanken) for the 12 month change in the consumer price index is unbiased? Results shows that for shorter horizons (h < 12) the mean forecast error is unbiased but for longer horizons its negatively biased when inference is done by Maximum entropy bootstrap technique. Can the unbiasedness be improved by strict ap- pliance to econometric methodology? Forecasting with a linear univariate model (seasonal ARIMA) and a multivariate model Vector Error Correction model (VECM) shows that when controlling for the presence of structural breaks VECM outperforms both prediction produced Riksbanken and ARIMA. However Riksbanken had the best precision in their forecast, estimated as MSFE

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Este estudo investiga os efeitos da estabilizaÃÃo da inflaÃÃo no Brasil nos Ãndices de preÃos regionais atravÃs da teoria da Paridade do Poder de Compra. Para tanto, utilizamos o Ãndice Nacional de PreÃos ao Consumidor Amplo, IPCA, abrangendo as nove regiÃes metropolitanas brasileiras durante o perÃodo de 1989 a 2011. Iniciamos nossa anÃlise com o teste de Perron e Yabu (2009) com o objetivo de verificar possÃveis quebras estruturais nas sÃries de cÃmbio real entre as regiÃes metropolitanas. Visando confirmar a hipÃtese da Paridade do Poder de Compra para o Brasil, aplicamos o teste de raiz unitÃria ERS (1996) bem como o teste de Kim (2000) posteriormente modificado por Harvey, Leybourne e Taylor (2006) para verificar possÃveis mudanÃas de persistÃncia nas sÃries. Durante o perÃodo analisado foi detectada uma diminuiÃÃo da persistÃncia das sÃries, creditamos esse fenÃmeno ao controle inflacionÃrio com o implemento do Plano Real, evidenciando que a estabilidade dos preÃos influi positivamente na validaÃÃo da hipÃtese da Paridade do Poder de Compra. / This study investigates the effects of inflation stabilization in Brazil in regional price indices through the theory of Purchasing Power Parity. We used the National Index of Consumer Prices Broad, IPCA, covering nine metropolitan regions during the period of 1989 to 2011. We begin our analysis with the test of Perron and Yabu (2009) in order to check for possible structural breaks in the series of real exchange rates between the metropolitan areas. To confirm the hypothesis of Purchasing Power Parity for Brazil, we apply the unit root test ERS (1996) as well as the test of Kim (2000) later modified by Harvey, Leybourne and Taylor (2006) to check for possible changes of persistence in the series. During the period analyzed was detected a decrease of the persistence of the series, we credit this phenomenon to the implement of the Real Plan, showing that price stability positively influence the validation of the hypothesis of Purchasing Power Parity.

nÃo hà / Este estudo analisa a evoluÃÃo do endividamento do Estado do CearÃ, tomando como indicador a razÃo entre a DÃvida Consolidada LÃquida (DCL) e a Receita Corrente LÃquida (RCL), verificando a existÃncia de quebras estruturais da dÃvida pÃblica, no perÃodo de 2003 a 2013, considerando que esta relaÃÃo constitui-se em um importante indicador por influenciar a tomada de decisÃo, no tocante a contrataÃÃo de operaÃÃes de crÃdito pelo Governo. Adicionalmente, à realizada uma anÃlise comparativa com os Estados da Bahia e Pernambuco. Para aferir a evoluÃÃo desta razÃo, empregam-se as metodologias desenvolvidas por Perron e Yabu (2009a, 2009b). Os resultados da anÃlise demonstraram que o Estado do Cearà vem mantendo o controle de seu endividamento, contribuindo para que a relaÃÃo DCL/RCL fique em patamares reduzidos. Desta forma, o Estado està cumprindo a meta estabelecida pela LRF. Os resultados do ensaio evidenciam que ocorreram quebras estruturais nos trÃs estados pesquisados. Antes das quebras estruturais, todos os estados apresentavam inclinaÃÃo negativa na razÃo DCL/RCL. O Cearà permanece no final de 2013, com a menor razÃo DCL/RCL entre os trÃs estados analisados, embora apresente uma tendÃncia crescente da razÃo DCL/RCL apÃs o 5 bimestre de 2009. Mesmo com a tendÃncia de crescimento identificada, o Estado do Cearà vem mantendo uma estratÃgia adequada e consistente, contribuindo para que o seu endividamento fique dentro dos limites definidos em lei. / The main purpose of this thesis is to shed some light on the indebtedness of Ceara and to analyze its development possibilities. We assume that an adequate evaluation of these possibilities should deal with the ratio between consolidated net debt (CND) and current net income (CNI). From this starting point, we verify if there are any structural breaks with respect the public debt. This evaluation comprehends the period which goes from 2003 to 2013. We also analyze the arguments in favor of minimal common requirements on (CND) â (CNI) and its relationship with these structural weakness. One is the fiscal requirement that says that governments consider such a relationship as an important indicator which plays a vital role on their decision makings such as credit operations. In addition, it will be made a comparative analysis bearing the States of Bahia and Pernambuco. To quantify over the ration between (CND) and (CNI), we employ throughout the thesis the methodologies formulated by Perron and Yabu (2009a, 2009b), respectively. The analysis results show that the State of Cearà still continues keeping a suitable strategy toward the maintenance and control of its indebtedness at supportable levels. And the reason is that the ratio between CND â CNI remains at reasonable levels. Also, as a positive outcome, the State is firmly respecting the Fiscal Responsability Act. The simulations show that there were structural breaks in the three states investigated, though before these all states had negative slope in the ratio CND â CNI. In late 2013 Ceara State appeared as the slightest CND â CNI between the three states analyzed, though showing a growing tendency with respect the CND â CNI after 5th quarter of 2009. Even this, the State of Cearà maintains an affirmative and consistent fiscal sustainability, in virtue of this is that its indebtedness is within the limits stipulated by Fiscal Responsibility Act.