This thesis provides a comprehensive history of the statistical background and uses of survival analysis, and then applies econometric duration analysis to examine the lifecycles of product lines within the microprocessor industry. Using data from Stanford University's CPUDB, covering Intel and AMD processors introduced between 1971 and 2014, the duration analysis uses both parametric and nonparametric estimators to construct survival and hazard functions for estimated product line lifetimes within microprocessor product families. The well-known and widely applied non-parametric Kaplan-Meier estimator is applied on both the entire sample as a whole, and segmented estimate that considers product line lifecycles of Intel and AMD separately, with median survival time of 456 days. The parametric duration analysis uses both the semi-parametric Cox proportional hazard model, and the fully parametric accelerated failure time model across the Weibull, Exponential and Log-Logistic distributions, which find modest association between higher clock speed and transistor count on diminishing expected time in the marketplace for microprocessors, while the number of cores and other attributes have no predictive power over expected survival times. It is expected that the transistor count and clock speed of a given processor's negative effect on expected duration, likely captures the co-trending of growth in transistor count with a larger marketplace and broader product categories. / Graduate

Data from longitudinal surveys give rise to many statistical challenges. They often come from a vast, heterogeneous population and from a complex sampling design. Further, they are usually collected retrospectively at intermittent interviews spaced over a long period of time, which gives rise to missing information and loss to follow-up. As a result, duration data from this kind of surveys are subject to dependent censoring, which needs to be taken into account to prevent biased analysis. Methods for point and variance estimation are developed using Inverse Probability of Censoring (IPC) weights. These methods account for the random nature of the IPC weights and can be applied in the analysis of duration data in survey and non-survey settings. The IPC estimation techniques are based on parametric estimating function theory and involve the estimation of dropout models. Survival distributions without covariates are estimated via a weighted Kaplan-Meier method and regression modeling through the Cox Proportional Hazards model and other models is based on weighted estimating functions. The observational frameworks from Statistics Canada's Survey of Labour and Income Dynamics (SLID) and the UK Millenium Cohort Study are used as motivation, and durations of jobless spells from SLID are analyzed as an illustration of the methodology. Issues regarding missing information from longitudinal surveys are also discussed.

Data from longitudinal surveys give rise to many statistical challenges. They often come from a vast, heterogeneous population and from a complex sampling design. Further, they are usually collected retrospectively at intermittent interviews spaced over a long period of time, which gives rise to missing information and loss to follow-up. As a result, duration data from this kind of surveys are subject to dependent censoring, which needs to be taken into account to prevent biased analysis. Methods for point and variance estimation are developed using Inverse Probability of Censoring (IPC) weights. These methods account for the random nature of the IPC weights and can be applied in the analysis of duration data in survey and non-survey settings. The IPC estimation techniques are based on parametric estimating function theory and involve the estimation of dropout models. Survival distributions without covariates are estimated via a weighted Kaplan-Meier method and regression modeling through the Cox Proportional Hazards model and other models is based on weighted estimating functions. The observational frameworks from Statistics Canada's Survey of Labour and Income Dynamics (SLID) and the UK Millenium Cohort Study are used as motivation, and durations of jobless spells from SLID are analyzed as an illustration of the methodology. Issues regarding missing information from longitudinal surveys are also discussed.

Forest resources are significant in Mississippi's ecology and economy, with 12.5 million acres of Non-Industrial Private Forest (NIPF). Frequent ownership changes with lower durations decrease the average parcel size. The study examined the trends of NIPF parcelization accommodating duration analysis and tax roll data to identify the length of ownerships in an eight-county study. Based on the results, lower duration of ownerships was associated with increased number of smaller parcels less than 11 acres and a substantial loss of large forests. The median duration of ownership was between 10 to 15 years and 59% were absentee NIPF owners. Duration analysis revealed the length of NIPF ownership was highly associated with the size of the forest, sawtimber price, an economic recession, and distance to the closest metropolitan city. Lower ownership durations and smaller parcels will limit economies of scale and alter the functionality and structure of the NIPFs in the future.

Due to widespread decentralization of spending responsibilities, increasing revenue power and borrowing capacity of sub-national governments, sub-national borrowing has become an increasingly important source of sub-national finance. While there are arguments for and against giving sub-national authorities room for raising their own financial resources, appropriate sub-national borrowing regulatory framework can reduce chances of defaults and fiscal crises. This dissertation investigates the effectiveness of sub-national borrowing regulations in maintaining fiscal sustainability. More precisely, it tests the hypothesis that is sub-national borrowing is restricted to financing capital investments (the “golden rule”), and if the sub-national governments are provided with some measure of revenue autonomy, then the sub-national borrowing should not endanger fiscal sustainability. Based on the sub-national government panel data for 57 countries between 1990 and 2008 and applying the system GMM estimator and the survival analysis, this dissertation provides support for this hypothesis. The results suggest that the “golden rule” is effective in maintaining fiscal sustainability at both general and sub-national government level. Sub-national tax autonomy, however, seems to have positive but very small marginal effect on fiscal sustainability. The obtained results also emphasize the risk of the soft budget constraint and the moral hazard. Significant central government financing may give encouraging signs to the sub-national governments to over-borrow and to expect being bailed out by the central government. The results obtained in this dissertation imply following policy recommendations. First, sub-national government borrowing does not have to endanger fiscal sustainability if the borrowing regulation framework is well designed and according to specific country circumstances. Second, reducing fiscal dependence on central government financing reduces the risk of moral hazard and improves the effectiveness of borrowing control in maintaining fiscal balance at the sustainable level.

Thesis advisor: Sanjay K. Chugh / Thesis advisor: Fabio Schiantarelli / My doctoral research focuses on the role of labor market frictions in shaping macroeconomic outcomes. I am currently pursuing three main lines of research that constitute the three chapters of this dissertation. The first chapter focuses on involuntary part-time employment as an additional margin used by firms to adjust to business cycle fluctuations. The chapter documents empirical regularities of involuntary part-time employment in the U.S. and furnishes a tractable analytical framework for studying this phenomenon that has gained so much attention in the years that followed the Great Recession. In the second chapter, which is joint work with Sanjay Chugh, Ryan Chahrour and Alan Finkelstein-Shapiro, we study the labor market wedge in the context of a search and matching model to understand how static and dynamic inefficiencies change over the business cycle. Measuring the labor market wedge and understanding its sources of movement is of great importance from a macroeconomic point of view, as existing research shows it holds a prominent place in explaining fluctuations in aggregate output. Finally, in the third chapter I study empirically the determinants of the job finding probability, a key object in the context of frictional labor markets. More specifically, I analyze how decisions on time allocation by the unemployed affect their chances of finding a job, and identify the activities that make more likely for an unemployed individual to receive and accept a job offer. Chapter 1. In recent years researchers and policymakers have shown renewed interest in involuntary part-time employment as a crucial indicator of labor market health. The fact that individuals have part-time jobs even though they would be willing to work more hours is evidence that resources in the economy are not employed at full capacity. This group represents almost 40 percent of total underemployment. Despite its large size and importance to policy-makers, surprisingly little literature addresses the empirical regularities or economic role this margin plays in determining labor market outcomes. In "Underemployment and the Business Cycle" I address several questions regarding involuntary part-time employment. First, how does involuntary part-time employment differ from the standard extensive and intensive margins? Second, what factors influence the choice of firms to use involuntary part-time workers? Third, how might economic policy contribute to the existence of involuntary part-time employment in the economy? And, fourth, have there been any changes over time in the response of involuntary part-time employment to changes in aggregate economic conditions and, if so, what explains them? To describe the empirical regularities of involuntary part-time employment, I use detailed micro-level data from longitudinally-linked monthly files of the Current Population Survey. A novel finding that emerges from the analysis of this dataset is that wages of involuntary part-time workers display higher volatility and lower persistence than those of their full-time counterparts, thus indicating a higher degree of flexibility. In addition, I find that changes in involuntary part-time employment are mostly explained by reallocation of workers from full-time to part-time positions within the firm, which involves more than just a mere reduction in hours worked. I then aggregate the data and compute business cycle statistics. Surprisingly, I find that the behavior of involuntary part-time employment resembles the behavior of unemployment more than the one of full-time employment. In fact, the results indicate that involuntary part-time employment is very volatile and strongly countercyclical. To understand the evidence I find at the micro and macro levels, I build an augmented search and matching model of the labor market featuring full-time and part-time employment, and a production function that combines both types of workers. The decision of whether a worker is full-time or part-time is made entirely by the firm, depending on the realizations of both aggregate and idiosyncratic productivity processes. The model is able to deliver the countercyclicality of involuntary part-time employment found in the data. The key mechanism to obtain this result is the relatively higher flexibility of part-time contracts that makes it more profitable for the firm to reallocate workers from full-time to part-time arrangements during recessions. Based on the model that captures key empirical facts, I conduct policy analysis to evaluate the effect of an increase in the cost of health insurance on involuntary part-time employment. The policy experiment predicts that an increase in the cost of health insurance provided by the firm to its full-time workers, such that their share in average full-time wages goes up by 1 percentage point, leads to an increase of steady state involuntary part-time employment by 10 percent, which nowadays would be equivalent to half a million additional involuntary part-time workers. I find evidence that involuntary part-time employment has become more volatile and persistent in the last 25 years. I study the impact that innovation in workforce management practices, a process that started in the 1990s and that has increased the degree of substitutability between full-time and part-time workers, may have had in changing the response over time of involuntary part-time employment to business cycle fluctuations. Impulse response analysis from the model indicates that an increase in the degree of substitutability makes involuntary part-time employment more sensitive to aggregate productivity shocks. Chapter 2. In "The Labor Wedge: A Search and Matching Perspective" we define and quantify static and dynamic labor market wedges in a search and matching model with endogenous labor force participation. Existing literature has generally centered on Walrasian labor markets in characterizing the inefficiencies, or ``gaps'', between labor demand and labor supply. However, given the conventional view in the profession that the matching process plays an important role in the labor market, the neoclassically-measured labor wedge suffers from a misspecification problem as it ignores the role of long-lasting relationships in explaining the cyclical pattern of the labor wedge. To construct the wedge we use a rigorously defined transformation function of the economy, which contains both the matching technology and the neoclassical production technology. Both technologies are primitives of the economy in the sense that a Social Planner must respect both processes. Given the model-appropriate transformation frontier and the household's static and dynamic marginal rates of substitution, we use data on the labor force participation rate, the employment rate, the vacancy rate, real consumption, real government spending, and real GDP to construct static and dynamic labor wedges. We find that, in a version of the model where all employment relationships turn over every period, the static labor wedge is countercyclical, a result that is consistent with existing literature. Once we consider long-lasting employment relationships, we can measure both static and dynamic wedges separately. We then find that, while the static wedge continues to be countercyclical, the dynamic (or intertemporal) wedge is procyclical. Since the latter is associated with the vacancy-posting decision of the firm, this result suggests that understanding the behavior of labor demand may be crucial to explaining the dynamic wedge. Our focus so far has been on obtaining a quantitative measure of both the static and dynamic wedges, and on analyzing their business cycle properties. Now we are working on extending this framework to provide a micro-founded explanation of the forces that could be driving the cyclical movements of the wedges. Chapter 3. Recent research has found that individuals who become unemployed allocate most of their forgone working hours into leisure rather than increasing the time devoted to job search activities. What is the rationale behind this decision? There are many factors that may affect the job search behavior of the unemployed. However, in this study I focus on a particular channel: the decision on how unemployed individuals allocate their time could be biased towards activities that increase their probability of finding a job. They might find more valuable to increase their social activities rather than looking formally for a job because this enhances their network, which could increase their chances of finding a job, even with less search effort. In "The Time Use Decisions of the Unemployed: A Survival Analysis", I conduct a duration analysis to estimate the effect of different time use allocations on the unemployment hazard rate using time use data from the Survey of Unemployed Workers in New Jersey. Defining "finding a job" as a failure, I estimate a single-spell, discrete-time duration model of unemployment with time-varying covariates using semi-parametric techniques. Given that I work with interval-censored data, I conduct the analysis using discrete time survival analysis techniques. The results indicate that education/training activities have a significant and positive impact on the hazard rate, i.e. they increase the probability that an unemployed worker finds a job, while leisure has the opposite effect. Furthermore, neither job-search nor networking have a significant effect on the hazard rate in the baseline specification. However, this result changes when incorporating into the regression interaction terms of these variables with a dummy that takes the value one if the individual is a long-term unemployed and zero otherwise. In this case, the coefficient associated with networking becomes positive and significant, while the coefficient of the interaction term is negative. This implies that networking has a positive effect on the hazard rate for short unemployment spells, but this effect weakens if the individual has been unemployed for a longer period. On the other hand, even after incorporating the interaction term, job search remains insignificant. These findings shed light on why individuals may not want to devote additional time to formal job search: it does not pay off with a higher likelihood of receiving a job offer, regardless of the length of the unemployment spell. On the other hand, other activities, such as investing in education or networking, are positively related to the probability of finding a job -- at least for short unemployment spells -- and thus it makes more sense for these individuals to devote more time to them.

(None) Technical Summary of Thesis: The topic of my thesis is currency crisis. Currency crises have been a recurrent feature of the international economy from the invention of paper money. They are not confined to particular economies or specific region. They take place in developed, emerging, and developing countries and are spread all over the globe. Countries that experience currency crises face economic losses that can be huge and disruptive. However, the exacted toll is not only financial and economic, but also human, social, and political. It is clear that the currency crisis is a real threat to financial stability and economic prosperity. The main objective of this thesis is to analyze the determinants of currency crises for twenty OECD countries and South Africa from 1970 through 1998. It systematically examines the role of economic fundamentals and contagion in the origins of currency crises and empirically attempts to identify the channels through which the crises are being transmitted. It also examines the links between the incidence of currency crises and the choice of exchange rate regimes as well as the impact of capital market liberalization policies on the occurrence of currency crises. The first chapter identifies the episodes of currency crisis in our data set. Determining true crisis periods is a vital step in the empirical studies and has direct impact on the reliability of their estimations and the relevant policy implications. We define a period as a crisis episode when the Exchange Market Pressure (EMP) index, which consists of changes in exchange rates, reserves, and interest rates, exceeds a threshold. In order to minimize the concerns regarding the accuracy of identified crisis episodes, we apply extreme value theory, which is a more objective approach compared to other methods. In this chapter, we also select the reference country, which a country’s currency pressure index should be built around, in a more systematic way rather than by arbitrary choice or descriptive reasoning. The second chapter studies the probability of a currency exiting a tranquil state into a crisis state. There is an extensive literature on currency crises that empirically evaluate the roots and causes of the crises. Despite the interesting results of the current empirical literature, only very few of them account for the influence of time on the probability of crises. We use duration models that rigorously incorporate the time factor into the likelihood functions and allow us to investigate how the amount of time that a currency has already spent in the tranquil state affects the stability of a currency. Our findings show that high values of volatility of unemployment rates, inflation rates, contagion factors (which mostly work through trade channels), unemployment rates, real effective exchange rate, trade openness, and size of economy increases the hazard of a crisis. We make use of several robustness checks, including running our models on two different crisis episodes sets that are identified based on monthly and quarterly type spells. The third chapter examines the links between the incidence of currency crises and the choice of exchange rate regimes as well as the impact of capital market liberalization policies on the occurrence of currency crises. As in our previous paper, duration analysis is our methodology to study the probability of a currency crisis occurrence under different exchange rate regimes and capital mobility policies. The third chapter finds that there is a significant link between the choice of exchange rate regime and the incidence of currency crises in our sample. Nevertheless, the results are sensitive to the choice of the de facto exchange rate system. Moreover, in our sample, capital control policies appear to be helpful in preventing low duration currency crises. The results are robust to a wide variety of sample and models checks.

Due to widespread decentralization of spending responsibilities, increasing revenue power and borrowing capacity of sub-national governments, sub-national borrowing has become an increasingly important source of sub-national finance. While there are arguments for and against giving sub-national authorities room for raising their own financial resources, appropriate sub-national borrowing regulatory framework can reduce chances of defaults and fiscal crises. This dissertation investigates the effectiveness of sub-national borrowing regulations in maintaining fiscal sustainability. More precisely, it tests the hypothesis that is sub-national borrowing is restricted to financing capital investments (the “golden rule”), and if the sub-national governments are provided with some measure of revenue autonomy, then the sub-national borrowing should not endanger fiscal sustainability. Based on the sub-national government panel data for 57 countries between 1990 and 2008 and applying the system GMM estimator and the survival analysis, this dissertation provides support for this hypothesis. The results suggest that the “golden rule” is effective in maintaining fiscal sustainability at both general and sub-national government level. Sub-national tax autonomy, however, seems to have positive but very small marginal effect on fiscal sustainability. The obtained results also emphasize the risk of the soft budget constraint and the moral hazard. Significant central government financing may give encouraging signs to the sub-national governments to over-borrow and to expect being bailed out by the central government. The results obtained in this dissertation imply following policy recommendations. First, sub-national government borrowing does not have to endanger fiscal sustainability if the borrowing regulation framework is well designed and according to specific country circumstances. Second, reducing fiscal dependence on central government financing reduces the risk of moral hazard and improves the effectiveness of borrowing control in maintaining fiscal balance at the sustainable level.

(None) Technical Summary of Thesis: The topic of my thesis is currency crisis. Currency crises have been a recurrent feature of the international economy from the invention of paper money. They are not confined to particular economies or specific region. They take place in developed, emerging, and developing countries and are spread all over the globe. Countries that experience currency crises face economic losses that can be huge and disruptive. However, the exacted toll is not only financial and economic, but also human, social, and political. It is clear that the currency crisis is a real threat to financial stability and economic prosperity. The main objective of this thesis is to analyze the determinants of currency crises for twenty OECD countries and South Africa from 1970 through 1998. It systematically examines the role of economic fundamentals and contagion in the origins of currency crises and empirically attempts to identify the channels through which the crises are being transmitted. It also examines the links between the incidence of currency crises and the choice of exchange rate regimes as well as the impact of capital market liberalization policies on the occurrence of currency crises. The first chapter identifies the episodes of currency crisis in our data set. Determining true crisis periods is a vital step in the empirical studies and has direct impact on the reliability of their estimations and the relevant policy implications. We define a period as a crisis episode when the Exchange Market Pressure (EMP) index, which consists of changes in exchange rates, reserves, and interest rates, exceeds a threshold. In order to minimize the concerns regarding the accuracy of identified crisis episodes, we apply extreme value theory, which is a more objective approach compared to other methods. In this chapter, we also select the reference country, which a country’s currency pressure index should be built around, in a more systematic way rather than by arbitrary choice or descriptive reasoning. The second chapter studies the probability of a currency exiting a tranquil state into a crisis state. There is an extensive literature on currency crises that empirically evaluate the roots and causes of the crises. Despite the interesting results of the current empirical literature, only very few of them account for the influence of time on the probability of crises. We use duration models that rigorously incorporate the time factor into the likelihood functions and allow us to investigate how the amount of time that a currency has already spent in the tranquil state affects the stability of a currency. Our findings show that high values of volatility of unemployment rates, inflation rates, contagion factors (which mostly work through trade channels), unemployment rates, real effective exchange rate, trade openness, and size of economy increases the hazard of a crisis. We make use of several robustness checks, including running our models on two different crisis episodes sets that are identified based on monthly and quarterly type spells. The third chapter examines the links between the incidence of currency crises and the choice of exchange rate regimes as well as the impact of capital market liberalization policies on the occurrence of currency crises. As in our previous paper, duration analysis is our methodology to study the probability of a currency crisis occurrence under different exchange rate regimes and capital mobility policies. The third chapter finds that there is a significant link between the choice of exchange rate regime and the incidence of currency crises in our sample. Nevertheless, the results are sensitive to the choice of the de facto exchange rate system. Moreover, in our sample, capital control policies appear to be helpful in preventing low duration currency crises. The results are robust to a wide variety of sample and models checks.

In this thesis, we examine labor market outcomes for the youth (ages 15-29) using microdata from several rounds of the Turkish Household Labor Force Survey (HLFS). We begin by examining demographic trends. We then rely on synthetic cohorts. The fact that the HLFS sample frame targets the civilian non-institutional population brings about difficulties in interpreting labor market indicators. We show that a more reasonable picture of schooling and work choices emerges when a simple correction for &lsquo / missing males&rsquo / who are doing their CMS and examine the effect of Compulsory Military Service (CMS) on the transition from school to work by using discrete hazard models. We also investigate the time it takes to find the first permanent job to shed light on the recent evolution of the transition from school to work.Using Cox Proportional Hazard Model, we examine the effects of structural reforms and macro-economic conditions, and the permanence of these effects. We are able to study the differences in the hazard of obtaining the first permanent job by education levels non-parametrically. Finally, we investigate the changes in the cumulative baseline hazards over time and test for the presence of gender differences in the hazard rates by using time varying covariates. With the help of these covariates, we are able to compute the time needed for the closure of the gender gap.