Esta tese tem como objetivo estudar a questão do desemprego a partir de três abordagens distintas: teórica, empírica e de história das idéias. Uma tese com essas características se faz relevante justamente por apresentar diferentes abordagens científicas sobre um tema tão caro à sociedade e à ciência econômica. Na abordagem de história das idéias, concluiu-se que foram os trabalhos de Lucas (1972a, 1972b) que, de fato, estabilizaram o conceito de \"taxa natural de desemprego\" na literatura econômica do pós-guerra, através da introdução da hipótese das expectativas racionais em um arcabouço de equilíbrio geral. É mostrado, através da análise de sua correspondência, no final dos anos 1960, que sua pesquisa sobre o tema estava, na verdade, intimamente ligada à pesquisa de Phleps, ao mesmo tempo em que não tinha conexão com a pesquisa de Friedman. No capítulo teórico, foi construído um modelo teórico de crescimento com restrição externa à la Thirlwall em que a taxa e crescimento da participação da força de trabalho emerge como a variável endógena que iguala a taxa de crescimento de longo prazo da oferta à taxa de crescimento de longo prazo da demanda. No capítulo empírico, foi mostrado através da evolução da razão saldo em transações correntes/PIB que a restrição de equilíbrio do balanço de pagamentos teve impacto no aumento de probabilidade do trabalhador formal transitar para o emprego informal, para o emprego por conta própria, para o desemprego e para fora da PEA, durante os anos 1980 e 1990, no Brasil. Sendo assim, esta tese espera ter cumprido seu papel de contribuir para com a literatura econômica sobre o desemprego através de análises originais em cada tipo de abordagem apresentada, sinalizando, assim, a riqueza da ciência econômica e valorizando esta tese, também, por explorar a pluralidade metodológica e a profundidade analítica. / The aim of this thesis is to study the unemployment issue from three different approaches: theoretical, empirical and history of ideas. A thesis with these features is relevant because it presents different scientific approaches to an important subject to society and to Economics. In the history of ideas\' approach, this thesis concluded that the works of Lucas (1972a, 1972b) stabilized the concept of \"natural rate of unemployment\" in the post-war economic literature through the introduction of rational expectations hypothesis into a general equilibrium framework. It is shown, through Lucas\'s correspondence in the end of the 1960\'s, that his research on the subject was, in fact, closely related to Phelps\'s research but not related to Friedman\'s research. In the theoretical approach, it was built a theoretical growth model with external constraint, à la Thirlwall, in which the rate o growth of labor force participation emerges as the endogenous variable that equalizes the long run rate of growth of supply with the long run rate of growth of demand. In the empirical approach, it was shown through the evolution of the current account/GDP ratio that balance of payments equilibrium constraint had impact in the raise of the probability of workers in formal jobs to move to informal Jobs, to self-employment jobs, to unemployment and to inactivity, during the 1980\'s and 1990\'s, in Brazil. Thus, this thesis hopes to have accomplished its role in contributing to economic literature on unemployment through original analysis in each kind of approach presented, showing the richness of Economics and, at the same time, increasing the value of this thesis for exploring the methodological plurality and the analytical deepness.

Darbe analizuojamas natūralus nedarbo lygis, Filipso kreivė. Darbo tikslas - įvertinti natūralų nedarbo lygį Lietuvoje. Pirmoje dalyje teoriškai nagrinėjama Filipso kreivė ir jos modifikacijos, kuri yra natūralaus nedarbo lygio teorinis pamatas, bei natūralų nedarbo lygį veikiantys faktoriai, analizuojamos vertinimo metodikos. Antroje dalyje analizuojami Filipso kreivę veikiančių faktorių dinamika Lietuvoje: valstybės išlaidos, komercinių bankų suteiktos paskolos, importo infliacija, naftos, dujų, elektros ir maisto žaliavų kainos. Analizuojami galimi Filipso kreivės struktūriniai lūžiai. Analizuojami natūralų nedarbo lygį veikinatys faktoriai: jaunimo nedarbo lygis ir santykinis dydis darbo jėgoje, emigracija, socialinės apsaugos lygis bei darbo produktyvumas, pateikiama natūralaus nedarbo lygio vertinimo metodologija. Trečioje dalyje vertinamos įvairių Filipso kreivių modifikacijų galiojimo Lietuvoje hipotezės bei vertinamas natūralus nedarbo lygis, apžvelgiami rezultatai ir jų patikimumas. Tyrime statistiškai patikimas Filipso kreivės modelis nebuvo rastas. Apskaičiuotas 12,04% Lietuvos natūralus nedarbo lygio įvertinimas yra tik iš dalies patikimas. Visi regresiniai modeliai parodė statistiškai reikšmingą neigiamą nedarbo lygio ir infliacijos priklausomybę. / Thesis is focused on natural rate of unemployment and variations of Phillips curve. Estimation of natural rate of unemployment in Lithuania is the main objective. In the first part Phillips curve and its variations, which is foundation for natural rate of unemployment as well as other infuencing factors are analysed on theoretical basis. Various estimation techniques are compared. In the second part various factors are analysed in the context of Phillips curve in Lithuania together with possible structural breaks in Phillips curve relationship. Conclusions are drawn from analysis of factors influencing natural rate of unemployment, particularly emigration and social security. Estimation methodology is specified in the second part. In the last part hipothesis of Phillips curve and natural rate of unemployment are tested. In conclusion, no statistically reliable model of Phillips curve based on empirical data is found, though all models proved negative inflation and unemployment relationship in Lithuania. Results show natural rate of unemployment to be 12,04%, though it is important to note, that results are drawn from statistically unreliable model.

Esta tese tem como objetivo estudar a questão do desemprego a partir de três abordagens distintas: teórica, empírica e de história das idéias. Uma tese com essas características se faz relevante justamente por apresentar diferentes abordagens científicas sobre um tema tão caro à sociedade e à ciência econômica. Na abordagem de história das idéias, concluiu-se que foram os trabalhos de Lucas (1972a, 1972b) que, de fato, estabilizaram o conceito de \"taxa natural de desemprego\" na literatura econômica do pós-guerra, através da introdução da hipótese das expectativas racionais em um arcabouço de equilíbrio geral. É mostrado, através da análise de sua correspondência, no final dos anos 1960, que sua pesquisa sobre o tema estava, na verdade, intimamente ligada à pesquisa de Phleps, ao mesmo tempo em que não tinha conexão com a pesquisa de Friedman. No capítulo teórico, foi construído um modelo teórico de crescimento com restrição externa à la Thirlwall em que a taxa e crescimento da participação da força de trabalho emerge como a variável endógena que iguala a taxa de crescimento de longo prazo da oferta à taxa de crescimento de longo prazo da demanda. No capítulo empírico, foi mostrado através da evolução da razão saldo em transações correntes/PIB que a restrição de equilíbrio do balanço de pagamentos teve impacto no aumento de probabilidade do trabalhador formal transitar para o emprego informal, para o emprego por conta própria, para o desemprego e para fora da PEA, durante os anos 1980 e 1990, no Brasil. Sendo assim, esta tese espera ter cumprido seu papel de contribuir para com a literatura econômica sobre o desemprego através de análises originais em cada tipo de abordagem apresentada, sinalizando, assim, a riqueza da ciência econômica e valorizando esta tese, também, por explorar a pluralidade metodológica e a profundidade analítica. / The aim of this thesis is to study the unemployment issue from three different approaches: theoretical, empirical and history of ideas. A thesis with these features is relevant because it presents different scientific approaches to an important subject to society and to Economics. In the history of ideas\' approach, this thesis concluded that the works of Lucas (1972a, 1972b) stabilized the concept of \"natural rate of unemployment\" in the post-war economic literature through the introduction of rational expectations hypothesis into a general equilibrium framework. It is shown, through Lucas\'s correspondence in the end of the 1960\'s, that his research on the subject was, in fact, closely related to Phelps\'s research but not related to Friedman\'s research. In the theoretical approach, it was built a theoretical growth model with external constraint, à la Thirlwall, in which the rate o growth of labor force participation emerges as the endogenous variable that equalizes the long run rate of growth of supply with the long run rate of growth of demand. In the empirical approach, it was shown through the evolution of the current account/GDP ratio that balance of payments equilibrium constraint had impact in the raise of the probability of workers in formal jobs to move to informal Jobs, to self-employment jobs, to unemployment and to inactivity, during the 1980\'s and 1990\'s, in Brazil. Thus, this thesis hopes to have accomplished its role in contributing to economic literature on unemployment through original analysis in each kind of approach presented, showing the richness of Economics and, at the same time, increasing the value of this thesis for exploring the methodological plurality and the analytical deepness.

We estimate a multivariate unobserved components stochastic volatility model to explain the dynamics of a panel of six exchange rates against the US Dollar. The empirical model is based on the assumption that both countries' monetary policy strategies may be well described by Taylor rules with a time-varying inflation target, a time-varying natural rate of unemployment, and interest rate smoothing. The estimates closely track major movements along with important time series properties of real and nominal exchange rates across all currencies considered. The model generally outperforms a benchmark model that does not account for changes in trend inflation and trend unemployment. (authors' abstract) / Series: Department of Economics Working Paper Series

Text in Afrikaans / Suid-Afrika ondervind reeds geruime tyd hoe en stygende vlakke van werkloosheid. Gedurende die tagtigerjare bet die opkoms van vakbonde 'n fundamentele herstrukturering van die Suid-Afrikaanse arbeidsmark veroorsaak en die styging in werkloosheid gedurende die tydperk word dikwels aan vakbondoptrede toegeskryf. In die studie word verskillende oorsake van werkloosheid aan die hand van die klassieke, Keynesiaanse, natuurlike werkloosheidskoers- en nie-versnellende-inflasiewerkloosheidskoersbenaderings ondersoek ten einde die invloed van vakbonde en loononaanpasbaarheid op werkloosheid te probeer bepaal. Ooreenkomste sowel as verskille tussen die teoriee word geidentifiseer. Dit wil voorkom asof vakbonde gedurende die tagtigerjare in Suid-Afrika deur middel van bulle invloed op . loonverhogings 'n betreklik geringe invloed op werkloosheid gehad bet en dat loononaanpasbaarheid geensins 'n beduidende faktor was nie. Dit blyk ook dat die Keynesiaanse benadering die toepaslikste raamwerk hied vir die ontleding van hoe vlakke van werkloosheid en die invloed van vakbonde daarop. · / High and rising levels of unemployment have been experienced in South Africa for quite some time. The rise in trade union activity during the eighties caused a fundamental restructuring of the South African labour market and the increase in unemployment during this period is often blamed on trade union activity. In this study the classical approach, the Keynesian approach, the natural rate of unemployment and the non-accelerating inflation rate of unemployment are used to examine the different causes of unemployment with the purpose of assessing the influence of trade unions and wage rigidity on the level of unemployment. Similarities as well as differences between the theories are identified. It appears that trade unions had a marginal effect on unemployment in South Africa during the eighties through their influence on wage increases and that wage rigidity was not a significant cause of unemployment during this period. The Keynesian approach seems to be the most appropriate framework to analyse the causes of high levels of unemployment as well as the influence of trade unions on unemployment. / Department of Economics / M. Comm (Economics)

Text in Afrikaans / Suid-Afrika ondervind reeds geruime tyd hoe en stygende vlakke van werkloosheid. Gedurende die tagtigerjare bet die opkoms van vakbonde 'n fundamentele herstrukturering van die Suid-Afrikaanse arbeidsmark veroorsaak en die styging in werkloosheid gedurende die tydperk word dikwels aan vakbondoptrede toegeskryf. In die studie word verskillende oorsake van werkloosheid aan die hand van die klassieke, Keynesiaanse, natuurlike werkloosheidskoers- en nie-versnellende-inflasiewerkloosheidskoersbenaderings ondersoek ten einde die invloed van vakbonde en loononaanpasbaarheid op werkloosheid te probeer bepaal. Ooreenkomste sowel as verskille tussen die teoriee word geidentifiseer. Dit wil voorkom asof vakbonde gedurende die tagtigerjare in Suid-Afrika deur middel van bulle invloed op . loonverhogings 'n betreklik geringe invloed op werkloosheid gehad bet en dat loononaanpasbaarheid geensins 'n beduidende faktor was nie. Dit blyk ook dat die Keynesiaanse benadering die toepaslikste raamwerk hied vir die ontleding van hoe vlakke van werkloosheid en die invloed van vakbonde daarop. · / High and rising levels of unemployment have been experienced in South Africa for quite some time. The rise in trade union activity during the eighties caused a fundamental restructuring of the South African labour market and the increase in unemployment during this period is often blamed on trade union activity. In this study the classical approach, the Keynesian approach, the natural rate of unemployment and the non-accelerating inflation rate of unemployment are used to examine the different causes of unemployment with the purpose of assessing the influence of trade unions and wage rigidity on the level of unemployment. Similarities as well as differences between the theories are identified. It appears that trade unions had a marginal effect on unemployment in South Africa during the eighties through their influence on wage increases and that wage rigidity was not a significant cause of unemployment during this period. The Keynesian approach seems to be the most appropriate framework to analyse the causes of high levels of unemployment as well as the influence of trade unions on unemployment. / Department of Economics / M. Comm (Economics)

[pt] Prever emprego e desemprego é de grande importância para praticamente todos os agentes de uma economia. Emprego é uma das principais variáveis analisadas como indicador econômico, e desemprego serve para os policy makers como uma orientação às suas decisões. Neste trabalho, eu estudo quais características das duas séries podemos usar para auxiliar no tratamento dos dados e métodos empregados para auxiliar no poder preditivo das mesmas. Eu comparo modelos de machine (Random Forest e Lasso Adaptativo) e Deep (Long short Term memory) learning, procurando capturar as não linearidades e dinâmicas de ambas séries. Os resultados encontrados sugerem que o modelo AR com Random Forest aplicado nos resíduos, como uma maneira de separar parte linear e não linear, é o melhor modelo para previsão de emprego, enquanto Random Forest e AdaLasso com Random Forest aplicado nos resíduos são os melhores para o desemprego. / [en] Forecasting employment and unemployment is of great importance for virtually all agents in the economy. Employment is one of the main variables analyzed as an economic indicator, and unemployment serves to policy makers as a guide to their actions. In this essay, I study what features of both series we can use on data treatment and methods used to add to the forecasting predictive power. Using an AR model as a benchmark, I compare machine (Random Forest and Adaptive Lasso) and deep (Long Short Term Memory) learning methods, seeking to capture non-linearities of both series dynamics. The results suggests that an AR model with a Random Forest on residuals (as a way to separate linear and non-linear part) is the best model for employment forecast, while Random Forest and AdaLasso with Random Forest on residuals were the best for unemployment forecast.