Peer-reviewed journal articles provide the data for this study, given that their findings undergird the quantitative data referenced by prominent organizations, courts, and policy-makers. The “Espy file”, based on the research of Major Watt Espy, Jr., is used to identify studies due to the dataset’s esteem and prolific usage. It is the largest known dataset of men’s and women’s executions in the United States since 1608 and has been of monumental significance to capital punishment research. The protocol established by the Preferred Reporting of Items for Systematic Reviews and Meta-Analyses (PRISMA) is the methodology followed due to its conformity to scientific standards and acceptance in scholarly communities. The initial sampling frame involved 613 studies which were narrowed to 79 peer-reviewed journal articles that cited or utilized the Espy file. The empirical findings justify the contention that past and current studies, while interdisciplinary, require new voices and approaches to contribute to the study of capital punishment. Mainstream death penalty research does not generally incorporate critical theories including, for example, gender, intersectional, Black feminist, Queer, and other theories that focus less on quantitative data and more on how capital punishment is a reflection of institutional, historical, and social processes that are hierarchical and defined by power. The findings suggest that not only are executed women removed from many analyses, but so are inclusionary methodologies and theoretical approaches that could bolster the legitimacy of academic studies (inside academia as well as the judicial system) and our understanding of capital punishment in general.