In randomized clinical trials where the effects of post-randomization factors are of interest, the standard regression analyses are biased due to unmeasured confounding. The instrumental variables (IV; Angrist et al., 1996) and G-estimation procedures under structural nested mean models (SNMMs;...

The primary aim of this thesis is the elucidation of covariate effects on the dependence structure of random variables in bivariate or multivariate models. We develop a unified approach via a conditional copula model in which the copula is parametric and its parameter varies as the covariate. We...

After treatment is found to be effective in a clinical study, attention often focuses on the effect of treatment duration on outcome. Such an analysis facilitates recommendations on the most beneficial treatment duration. In many studies, treatment duration is left to the discretion of the...

In causal inference for longitudinal data, standard methods usually assume that the underlying processes are discrete time processes, and that the observational time points are the time points when the processes change values. The identification of these standard models often relies on the...

Two-stage predictor substitution (2SPS) and the two-stage residual inclusion (2SRI) are two approaches to instrumental variable (IV) analysis. While 2SPS and 2SRI with linear models are well-studied methods of causal inference, the properties of 2SPS and 2SRI for logistic binary outcomes have...

This thesis examines causal inference related topics involving intermediate variables, and uses Bayesian methodologies to advance analysis capabilities in these areas. First, joint modeling of outcome variables with intermediate variables is considered in the context of birthweight and censored...

This paper investigates the determinants of participation and performance of tobacco contract farmers, and the effects of participation on overall crop and household incomes in the Zambezi Valley of Mozambique. We test the existence of threshold effects in land holdings and educational...

This dissertation introduces three novel approaches for the econometric evaluation of heterogeneous treatment effects. The proposed methods consider the effects of a binary treatment on different characteristics of the outcome distribution.Section 1 proposes an estimation method for various...

Este artículo aborda la siguiente pregunta: ¿cuál habría sido el PIB per cápita del área del euro si no se hubiese creado la unión monetaria? Para intentar contestarla, utilizamos la metodología de control sintético [Abadie y Gardeázabal (2003) y Abadie et al. (2010)]. Nuestros...

In the ¯rst of the essays, I reassess the relationship between premarital cohab-itation and marital instability both theoretically and empirically. It has become astylized fact that premarital cohabitation is positively correlated with the likelihood ofmarital dissolution. This is...