ABSTRACT
The research questions that motivate most quantitative studies in the health, social, and behavioral sciences are not statistical but causal in nature. For example, what is the efficacy of a given treatment or program in a given population? Whether data can prove an employer guilty of hiring discrimination? What fraction of past crimes could have been avoided by a given policy? What was the cause of death of a given individual in a specific incident? These are causal questions because they require some knowledge of the data-generating process; they cannot be computed from the data alone.
