Il presente lavoro raccoglie 4 contributi sul tema dei differenziali sui tassi di interesse esistenti tra i membri dell'unione monetaria europea. / I investigate the determinants of sovereign yield spreads in EMU.

Il primo Capitolo trae origine dall’evidenza dello scarso rendimento scolastico dei bambini che vivono nelle case popolari italiane. Gli obiettivi di questo paper sono due: uno è di verificare l’esistenza di un effetto “ghetto” tra pari, l’altro è di verificare l’esistenza di un effetto “ghetto” crescente (nella dimensione della casa popolare) e/o l’esistenza di effetto “struttura” (“casermoni”). L’analisi suggerisce un effetto causale sfavorevole delle case popolari sull’evasione scolastica delle ragazze e un effetto sfavorevole dei “casermoni” sulla bocciatura, per le ragazze che vivono nelle grandi città. Per le altre variabili educative la difficoltà di isolare l’effetto dell’ambiente familiare non permette di trarre delle considerazioni conclusive. Il contributo del secondo Capitolo è di investigare se la diversità etnica delle scuole ha un impatto sui voti dei bambini e per chi è importante. Proviamo anche a chiarire quali meccanismi possono esserci dietro. Usiamo un ricco data-set sull’istruzione primaria nei Paesi Bassi. Troviamo che la diversità etnica ha un impatto positivo sui voti degli studenti della minoranze etniche, specialmente per i voti nelle abilità linguistiche e per gli studenti più grandi. Troviamo anche una relazione negativa tra la diversità etnica e l’ambiente sociale della scuola, che può parzialmente spiegare l’incremento nei voti come il risultato di un ambiente più competitivo. Nel 2005 l’Italia lanciò un’importante politica di promozione per incentivare le iscrizioni a particolari corsi di laurea scientifici. L’obiettivo del terzo Capitolo è di valutare l’efficacia di questa politica. Inoltre, controlliamo se la policy è stata efficace sia per i maschi che per le femmine. Infine, controlliamo se il programma ha generato effetti al di fuori della portata della policy. I risultati mostrano un effetto positivo e significativo della politica “Progetto Lauree Scientifiche” sui corsi di laurea scientifici designati e non e un effetto positivo e trasversale tra le materie. Comunque, se la politica ha un considerevole impatto sulla scelta del corso di laurea per i maschi, non sembra avere alcun effetto per le femmine. / The first Chapter originates from the evidence of the low school achievement of children living in Italian public housing. The aims of this paper are two: one is to verify the existence of a "ghetto" peer effect, the other is to verify the existence of an increasing "ghetto" effect (in the size of the project) and/or the existence of an amenity effect (high-rise projects). The analysis suggests an unfavorable causal effect of public housing on school evasion for girls and an unfavorable effect of high-rise projects on grade repetition, for girls living in big cities. For other educational outcomes the difficulty to isolate the family background effect does not allow us to draw conclusive comments. The contribution of the second Chapter is to investigate whether the ethnic diversity of schools has an impact on the test scores of children and for whom it matters. We also try to shed some light on the mechanisms there can be behind. We use a rich data-set about primary education in the Netherlands. We find that ethnic diversity has a positive impact on the test scores of minority students, especially for language skills and older students. We also find a negative relationship between ethnic diversity and school's social environment, that can partly explain the gains in test scores as a result of a more competitive environment. In 2005, Italy launched an important promotion policy to boost enrolments in selected scientific bachelors. The aim of the third Chapter is to evaluate the efficacy of this policy. Moreover, we check whether the policy has been effective for both males and females. Finally, we check whether the program generates effects outside the scope of the policy. The results show a positive and significant effect of the policy "Progetto Lauree Scientifiche" on targeted and non targeted scientific bachelors and positive cross treatment effects across subjects. However, if the policy has a considerable impact on the bachelor's choice for males, it does not appear to have any effect for females.

This thesis focuses on the analysis of heavy-tailed distributions, which are widely applied to model phenomena in many disciplines. The definition of heavy tails based on the theory of regular variation highlights the importance of the tail index, which indicates the existence of moments and characterises the rate at which the tail decays. Two new approaches to make inference for the tail index are proposed. The first approach employs a regression technique and constructs an estimator of the tail index. It exploits the fact that the behaviour of the characteristic function near the origin reflects the behaviour of the distribution function at infinity. The main advantage of this approach is that it utilises all observations to constitute each point in the regression, not just extreme values. Moreover, the approach does not rely on prior information on the starting point of the tail behaviour of the underlying distribution and shows excellent performance in a wide range of cases: Pareto distributions, heavy-tailed distributions with a non-constant slowly varying factor, and composite distributions with heavy tails. The second approach is motivated by the asymptotic properties of a special moment statistic, the so-called partition function. This statistic considers blocks of data and is generally used in the context of multifractality. Due to the interplay between the weak law of large numbers and the generalised central limit theorem, the asymptotic behaviour of the partition function is strongly affected by the existence of moments even for weakly dependent samples. Via a quantity, the scaling function, a graphical method to identify the existence of heavy tails is proposed. Moreover, the plot of the scaling function allows one to make inference for the underlying distribution: with infinite variance, finite variance with tail index larger than two, or all moments finite. Furthermore, since the tail index is reflected at the breakpoint of the plot of the scaling function, this gives the possibility to estimate the tail index. Both these two approaches use the entire distribution, not just the tail, to analyse the tail behaviour. This sheds a new light on the analysis of heavy-tailed distributions. At the end of this thesis, these two approaches are used to detect power laws in empirical data sets from a variety of fields and contribute to the debate on whether city sizes are better approximated by a power law or a log-normal distribution.

Despite the great efforts scholars have devoted to the study of migration a unified and coherent theory of international migration does not yet exist. Particularly, only in recent years, scholars have developed models of labor mobility to take into account social interaction across agents. Similarly, empirical analysis lacks an adequate approach to social interaction in migration, often using very rough measures as, for example, the stock of compatriots in the receiving country. The aim of this dissertation is to examine economic migrants decision to migrate, focusing specifically on potential migrants who can choose if and where to migrate, and which conditions facilitate their migration. It investigates how wealth, social networks and education interact in determining householdsâ€TM migration strategies and the aggregate dimension and composition of migration flows. Household income maximization strategy evaluates migration as a possible, but costly investment. In a context of underdeveloped financial and insurance markets, budget constraints play a key role in determining migration behavior. Poorer households have higher incentives, but fewer opportunities to migrate, whereas better-off households have fewer incentives, but greater possibilities of migrating. Social networks, reducing costs and risks of migration and thus counterbalancing budget constraints, mitigate this effect and allow new social strata to migrate. In the empirical analysis we examine Mexican migration to the U.S., proposing two new tools to apply in empirical analysis and showing that household and community networks act as complements in the probability of migration, and as substitutes in the optimal number of migrants. We also examine migration to the U.S. from five Central American countries, comparing findings with those obtained for Mexico.

The idea that public debt may represent a burden for the economic system as a whole has distant origins and focuses on who and how should pay for debt, and with what consequences on the economy. Nevertheless, particularly influential both for academic research and the implementation of the fiscal corrective policies was the empirical paper proposed by Reinhart and Rogoff in 2010 at the dawn of the crisis. Reinhart and Rogoff (2010), in a large panel of countries, identified a critical threshold of 90% of the debt-to-GDP ratio beyond which debt is harmful to growth. Several countries in the world were fast approaching that threshold or already were well beyond it. Though Reinhart and Rogoff’s work was affected by many flaws, it has spurred buoyant empirical research in search of the general debt thresholds above which growth is jeopardised by public debt. Further works have supported the existence of critical debt-to-GDP ratios under various time and space observational fields, but results of these researches are inconclusive or controversial, as discussed in Chapter 2. Country-specific characteristics and contingencies play in fact a prominent role, thus prompting a branch of literature that attempts to comprehensively understand the debt-growth relationship and its determinants (see for instance Panizza and Presbitero, 2014; Eberhardt and Presbitero, 2015). In contrast with the findings of the broad threshold literature and of many theoretical models, the idea that public debt is always harmful to economic growth has partially been reconsidered in the last few years. Nevertheless, the existence of a linkage between debt and growth has not been rejected: the long-run relationship between such macroeconomic variables is inevitably and broadly affected by heterogeneous factors. However, in retrospect and as emerges in Chapter 1, one may say that the empirical pursuit of the debt-to-GDP threshold harmful to growth lacks deeper foundational work: why should we expect a negative public debt-growth relationship? In addition, if such a relationship exists, why should it take the specific form of a threshold of the debt-to-GDP ratio, and why should we expect this threshold to be equally valid across time and space? These questions are the starting point of this Doctoral Thesis, which is organised as follows. Chapter 1 surveys the theoretical literature concerning public debt and economic growth, aiming at finding a theoretical foundation for the debt-threshold literature. Overall, there is no clear and straightforward answer to the questions of why we should expect a negative public debt-growth relationship in the first place, why it should take the specific form of a threshold of the debt-to-GDP ratio, and why we should expect this threshold to be equally valid across time and space. Or, from another perspective, there are many possible answers and many elements affecting them, thus reflecting the complexity of the argument, as well as the variety of the empirical situations. In particular, the literature that I examine, on the one hand offers a rich variety of explanations and insights to researchers of the debt-growth relationship but, on the other, it does not provide any one-way conclusion: the relationship may be negative, positive, or even no relationship may exist, both from a theoretical and an empirical point of view. Even less is theoretically founded the existence of a general debt-to-GDP threshold above which growth is consistently stifled. Each country’s specific characteristics, circumstances, and events have an overwhelming importance that cannot be encapsulated in a single general law. In Chapter 1, I also present a fiscal model of endogenous growth that may help address the theoretical issues in an orderly and consistent manner along two specific coordinates of debt assessment: sustainability/unsustainability, and efficiency/inefficiency. The thrust of the model is that no meaningful assessment of debt and its effect on growth at any point in time is possible without reference to the whole debt trajectory and the specific state of the economy along the trajectory. Chapter 2 reviews the empirical literature and focuses on the debt-growth relationship from an econometric point of view. As before, it is difficult to derive a univocal conclusion on the nature of such a relationship on the basis of the literature’s findings: the existence of a significant negative relationship between debt and growth is the predominant thinking, though in contrast with the conclusions of several works. For these reasons, the aim of Chapter 2 is to go to the roots of the debt-growth relationship, to investigate whether the outstanding debt and the GDP are linked. To this end, I have adopted a research methodology that differs from the most common employed in the literature on debt-to-GDP thresholds. First, my analysis does not hinge on any specific theory, and it should not be considered as a proof of a specific theoretical statement. Rather, it is based on the approach outlined by Hoover et al. (2008) and aims at understanding "what the data say" without imposing aprioristic theoretical structures. A second methodological choice consistent with this approach is to treat the (growth of the) amount of public debt and (the growth of) GDP as the two genuine primitives, without imposing the debt-to-GDP ratio as a primitive itself. In fact, for this to be possible, the two underlying primitives should display well defend statistical properties, namely cointegration and convergence towards a long-term equilibrium value, which are usually not tested in the literature. Third, I believe that the heterogeneity, or non-generality, of results that I have pointed out before should be taken as an intrinsic feature of the problem at hand, so that a viable strategy is to restrict, rather than expand, the observational field. I have set time and space limits to my dataset by purpose: my analysis is based on a panel dataset including quarterly data for 25 Eastern and Western European countries from 1999Q1 to 2015Q4. The Eurozone represents a unique "field experiment" of a large number of countries where some key conditioning factors of fiscal policy are common and exogenous, namely fiscal targets and rules, monetary policy, and the exchange rate with the rest of the world. The main result is that a long-run equilibrium relationship between GDP and debt exists for some countries ? and debt and GDP tend to adjust towards it ? but it is not generalisable. Where a relationship exists, it does not always imply that the debt-to-GDP ratio may be the appropriate variable for describing it. Moreover, cross-country heterogeneity and the role of the financial crisis and of the austerity periods remain substantial and overwhelming factors. Therefore, a unique equation describing the GDP-debt relationship does not seem to exist, which entails the impossibility to derive a meaningful general debt-to-GDP threshold. Thus far I have focused on the general relationship between debt and growth from both the theoretical and the empirical points of view. Turning to the analysis of the Sovereign Debt Crisis and of the austerity period, Chapter 3 attempts to explain what has driven austerity ? measured as the first difference of the cyclically adjusted structural primary balance ? within a dataset of 28 European countries. In the first part of this chapter I present a correlation analysis that describes the relationship between the variable austerity and each of the considered determinants, that are brought back to four main sets of variables: fiscal discipline, market discipline, fiscal consolidation, and macroeconomic stabilisation. The second part implements a panel econometric analysis based on the principal component factor analysis and on the pooled partial common correlation effect estimator. Results show that the variables and factors of the analysis are not able to fully explain austerity, though an important contribution is provided by the enforcement of the Eurozone fiscal rules (the adoption of excessive deficit procedures) and is partially counterbalanced by the cyclical position of the economy. The last chapter, Chapter 4, aims at gaining insight into the role of debt and government expectations and their impact on growth under uncertainty conditions. In fact, it is possible that the effects of austerity measures in some countries, for instance the so-called PIIGS, were amplified by uncertainty. My ambition is to relate austerity with consumers’ expectations, thus studying whether and when consumers’ beliefs about public debt and government intervention affect their consumption, savings, and tax compliance choices with a direct impact, at the aggregate level, on economic growth. Therefore, Chapter 4 implements a laboratory experiment to study how people react in a generalized framework in which public debt may be unexpectedly reduced. The debt dynamics arises endogenously: within a public good game, taxes are collected from all participants and are used to cover a given level of public expenditure, which is then equally distributed to the same participants at the beginning of each round. If the collected amount of taxes is lower than what the public expenditure would require, a deficit is generated. Moreover, reproducing a forced withdrawal, the outstanding amount of public debt can be reduced upon accessing subjects’ savings. Within this setting, expectations are directly elicited by asking subjects if they believe that public debt is going to be reduced, and if they think that the other subjects believe that public debt is sustainable. Therefore, it is possible to identify whether and how agents’ allocations and expectations are affected by the public debt path. As mentioned above, a peculiarity of my approach is the endogenous dynamics of public debt: not only it avoids introducing predetermined dynamics, but also increases the ecological validity of the experiment. Participants are indeed more psychologically involved in the debt mechanism and they might feel responsible for the raise in debt. On the other hand, an exogenous dynamics could depict public debt and tax compliance as irrelevant. Results show that this experimental framework is characterized by relatively high and often increasing aggregate savings and relatively low and decreasing aggregate consumption. Interestingly, an increase in the debt-reduction expectations and a decrease in the perceived debt sustainability are also found to explain savings and consumption behaviours, as is shown in the econometric part of Chapter 4.

Negli anni ’80, paesi in via di sviluppo (DCs) e paesi meno sviluppati (PMS) hanno subito cambiamenti strutturali, muovendosi da politiche di sostituzione di importazione a strategie di liberalizzazione. Questi paesi hanno assistito ad una crescita dinamica risultata dall’aumento della produttività dovuto alla maggiore esposizione delle industrie locali alla concorrenza, dall'aumento delle importazioni tecnologiche incarnate in capitale e in beni intermedi, e ad una maggiore diffusione di conoscenze e informazioni. Questo lavoro esamina come liberalizzazione commerciale ed aggiornamento tecnologico abbiano influito sull’occupazione in paesi DCs e PMS, e studia il fenomeno del cambiamento tecnologico skill biased. Si esaminano il settore manifatturiero turco tra il 1980-2001 e quello etiope tra il 1996-2004. Questo studio, basato sul System Generalized Method of Moments (GMM-SYS), implementa un quadro dinamico di due equazioni che raffigurano tendenze occupazionali a livello enterprise per lavoratori qualificati e non qualificati. I risultati confermano l'aspettativa teorica che DCs e LDC affrontano fenomeni di skill-biased technological change e incrementano il potere d’importazione di tecnologia, aumentando il divario d’occupazione tra lavoratori qualificati e non qualificati. Tuttavia, le cause specifiche di skill-bias e la portata del loro effetto possono variare in base a diverse infrastrutture istituzionali e capacità nazionali. / In the 1980's developing countries (DCs) and least developed countries (LDCs) underwent structural changes, moving from import substitution policies to liberalization strategies. These countries witnessed a dynamic growth effect that emerges from productivity growth due to increased exposure of local industries to competition, increased technological imports embodied in capital and intermediate goods, and to the transfer of knowledge. This work looks into the employment impact of trade liberalization and technological upgrading in DCs and LDCs, and studies the phenomenon of skill biased technological change in those countries. It takes the case of the Turkish manufacturing sector for the period 1980 - 2001, and the case of the Ethiopian manufacturing sector for the period 1996 - 2004. It deploys System Generalized Method of Moments (GMM-SYS) procedure to this effect, implementing a two-equation dynamic framework that depicts enterprise-level employment trends separately for skilled and unskilled workers. The results confirm the theoretical expectation that DCs and LDCs face the phenomena of skill-biased technological change and skill-enhancing technology import, both leading to increasing the employment gap between skilled and unskilled workers. However, the specific determinants of skill bias and the size of their effect can differ due to diverse institutional infrastructures and national capabilities.

La misurazione del crimine in Europa è difficile a causa delle diverse definizioni giuridiche dei reati e dalle differenti metodologie utilizzate per la raccolta di dati nei paesi Europei. L’Unione Europea produce indicatori strutturali in grado di misurare e confrontare le caratteristiche dei paesi: gli indicatori sociali possono aiutare a monitorare e analizzare le condizioni di vita e la qualità della vita e a contestualizzare il crimine descrivendo l’Europa d oggi. Sulla base di tre macro teorie criminologiche (modernizzazione, civilizzazione e opportunità) alcuni indicatori sociali sono selezionati e incrociati con i livelli di crimine così da poter identificare dei fattori di rischio per le diverse tipologie di reati e per valutare la validità di queste teorie in Europa. Infine l’uso di tecniche statistiche avanzate (cluster analysis) permetterà di identificare degli insiemi omogenei di paesi, per poter analizzare e confrontare l’andamento temporale tra i fattori di rischio identificati e il crimine in Europa. / Measuring crime in Europe is problematic because many different legal concept definitions and statistic collecting practices have been embraced in each country. In recent years, numerous efforts have been made to further this overarching goal and today, there are sources that present more comparable information on crime in Europe. At the same time, the European Union has produced broadly agreed upon structural indicators, called ‘social indicators’, to systematically report, monitor, and analyze living conditions and quality of life. These indicators help to contextualize crime by describing and relating to today’s European realities. On the basis of three macro theoretical paradigm indicators (the civilization theory, modernization theory, and opportunity theory), a set of social indicators will be selected and cross-examined with crime rates recorded in Europe. This endeavour will first test the relationship between the social indicators and different types of crimes in order to assess the validity of the theoretical frameworks across Europe as a whole. Second, it will identify a set of risk factors for the selected types of crimes. After that, using advanced statistical techniques (cluster analyses) to identify homogeneous sets of countries across Europe, the comparison will take into account the evolution of crime levels in two selected, averaged periods between 1990 and 2007. Crime trends will be compared and cross-checked with social indicator tendencies to explain crime variations over time.

This thesis explores the relation between fiancial stability and macroeconomic policy. The first chapter tackles the topic of financial stability from the point of wiev of a the single bank. In that model banks take explicitly into account the probability of default of their counterparties on the interbank market. In this way, an endogenous constraint to the credit supply is defined. That constraint evolves along the business cycle. I show that monetary policy alone is not able to ease credit conditions during a crisis. The second chapter nests a complex network model inside a state-of-the-art DSGE model. Using the tools of network analysis it is possible to trace how contagion spreads between banks (i.e. what is the likelihood that the default of one bank spreds to other banks, how many institution are affected) and how its probability avolves following exogenous shocks. With this tool I test partial equilibrium macropolicy tools (i.e. direct lendings to banks) and the effectiveness of monetary policy during crisis. Finally, in the last chapter I analyze, with high frequency data, the impact of conventional and unconventional monetary policy surprises, finding that the response of markets to menetary policy increased over time. / Questa tesi studia la relazione tra stabilità finanziaria e politica economica. Il primo capitolo della tesi affronta l'argomento della stabilità finanziaria dal punto di vista della singola banca. In quel modello ciascuna banca tiene esplicitamente in considerazine la probabilità di insulvenza delle sue controparti sul mercato interbancario. In questo modo si genera un vincolo endogeno all'offerta di credito. Tale vincolo evolve con il ciclo economico. Il modello mostra come la politica monetaria da sola non sia sufficiente a migliorare le condizioni del credito sui mercati finanziari dureante le crisi. Il secondo capitolo inserisce un modello di network all'interno di un mdoello DSGE standard. Analizzando il modello di network è possibile seguire come il contagio si diffonda tra le banche (qual è la probabilità che l'insolvenza di una banca si diffonda ad altre, qaule il numero di istituzioni coinvolte) e come tale probabilità evolva a seguito di shock esogeni. Con questi strumenti è possibile valutare politiche microeconomiche (per esempio prestiti diretti alle banche) e l'efficacia della politica moentaria durante le crisi. Infine, nell'ultimo capitolo, utilizzando dati ad alta frequenza, stimo l'impatto di shock di politica monetaria (convenzionali e non) trovando che la sensibilità dei mercati è aumentanta nel tempo.

This thesis examines three main themes, firms productive efficiency, internationalisation of African firms, and effect of liberalisation policies on market power and market imperfections. The thesis combines two main strands in economics literature in accessing the three main themes of the papers. The first strand regards methodological approaches to estimate a production function from which productive efficiency can be computed. Consistent estimation of productive efficiency is a necessary condition to analyse firm behaviour and their response to trade policies. The thesis critically examines methodologies to estimate productive efficiency. The second strand, international trade and industrial development, analyse firms behaviour in foreign market as well as firms responses to trade liberalisation policies and their overall impact on structural transformation. The two strands of literature examined in this thesis resulted in three independent papers, each of which addresses specific issues along the spectrum of productive efficiency estimation, internationalisation, and market power.

This thesis contains four closely related essays which address the empirical issues pertaining to the causes, consequences, and households’ responses to food price shocks in Uganda. The first essay investigates the nature of volatilities in agricultural commodity prices in Uganda between 2000 and 2012 by focusing on six key food staples, namely matooke, cassava, maize, sweet potatoes, beans, and millet flour. It studies the behavior of monthly price volatilities of these commodities, examines the extent of their volatility spillovers, identifies their macroeconomic and environmental drivers, and uncover their differential impacts using respectively the General Autoregressive Conditional Heteroscedastic (GARCH), the Vector Autoregressive (VAR) and the Seemingly Unrelated Regression (SUR) models. I find evidence that both unconditional and conditional price volatilities have significantly increased since January 2008 for most commodities, period of turmoil in the global food markets. The GARCH (1, 1) estimates indicate a strong persistence in volatility for most commodities while results from the Exponential GARCH (1, 1) models suggest the presence of asymmetric and leverage effects of unexpected price shocks for half of the commodities. In addition, the VAR estimation results detect limited and mostly unidirectional spillover effects across food commodities. Finally, historical price volatilities of most commodities are found to be primarily affected by volatilities in consumer price indices, fuel prices, and rainfall, with less evidence of strong seasonality effects as previously reported. The second essay presents an empirical analysis of the welfare impacts of food price changes in Uganda using three waves of the Uganda National Panel Surveys (UNPS) spanning over the years 2005-2011. It theoretically investigates the implications of labor market imperfections and households’ heterogeneity in terms of their net positions in both food and labor markets and compares welfare estimates between separable and non-separable models. Through the estimations a panel stochastic production frontier function and a censored-Quadratic Almost Ideal Demand Systems (QUAIDS) with expenditure and shadow wage endogeneities, the results suggest that the welfare effects of price changes (measured in terms of compensating variations) were globally lower in the non-separable agricultural model, implying a high degree of labor market frictions. Furthermore, I find that the welfare effects were unevenly distributed both within and between household groups. Particularly, although agricultural households benefited from price increases as a group between 2005/6 and 2009/10, both significant and insignificant net buyers did suffer from price changes. Moreover, results from non-parametric estimations show that households at the extremes of the welfare distribution were more severely hit by food price instabilities than others. Finally, the essay suggests that the important dynamics in the net market positions observed during the sample period might be attributed to a cost-benefit analysis related to the potential welfare effects of food prices. The third essay explores the question of crop choices and land allocations in environments where farmers face uncertainties about end-of-season output prices and yield levels, weather variability, and formulate expectations about their future levels. Indeed, in the absence of credit and/or insurance markets, farmers are widely expected to adjust their land allocation decisions as a management tool against agricultural and market-related risks. However, little is actually known about the likely differential effects of each of these risk components on farmers’ decisions, particularly when current decisions are allowed to depend on previous choices. Using a nationally representative panel data set for agricultural households in Uganda spanning over the years 2005 – 2012, the paper proposes to investigate the role played by both price and yield risks on farmers’ crop choices and area allocations using a multivariate generalization of the Heckman-type two-step procedure: a multivariate crop selection and a conditional acreage share models. The crop selection problem is modeled as a dynamic multivariate probit regression and estimated through Simulated Maximum Likelihood and the Geweke Hajivassiliou Keane simulator, whereas the conditional acreage share model is estimated using a dynamic multivariate fractional logit model. In both the multivariate crop selection and acreage share models, the results reveal that, while own expected prices and yields are among the main drivers of farmers' crop choices and land share allocations, farmers are found to be more sensitive to changes in expected yield levels than in expected end-of-season output prices. In addition, yield risks, temperature and rainfall volatility appear to have more impact on acreage share decisions than market price risks. Finally, household characteristics are found to play a marginal role in explaining farmers’ crop selection and acreage allocation decisions. The fourth and last essay develops a modified standard Ramsey model to analyze households’ welfare growth and test the assumption that differential exposure to food price shocks leads to different welfare trajectories and to potentially increased risks of poverty traps. The essay focuses on two welfare indicators, namely consumption levels and asset indices, and employs a battery of econometric methods, ranging from parametric GMM fixed effects models to locally weighted scatterplot smoother (LOWESS), local polynomial regressions, and Ruppert et al’s (2003) semi-parametric penalized splines to address nonlinearities in welfare dynamics, identify and locate critical welfare thresholds, and test for the presence of single against multiple welfare equilibria. Using the full sample, I find nonlinearities in welfare dynamic paths and reduction in the growth rates of both consumption levels and assets holdings as a consequence of exposure to food price and asset shocks. However, there is no evidence of poverty traps caused by households’ exposure or vulnerability to food price shocks, but instead I identify only a single dynamic stable equilibrium, located slightly above the official poverty, towards which Ugandan households are converging in the long run. Finally, when disaggregating households into different sub-groups sharing similar characteristics, the empirical results reveal that Ugandan households are converging towards specific welfare equilibria, depending on their initial conditions, demographic characteristics, the extent of their vulnerability and differential exposure to food price shocks. Particularly, I found that, households exposed to food price shocks or above the vulnerability threshold index are expected to move in the long run to welfare equilibria located at lower levels than their unexposed or less vulnerable counterparts.