In this critical review of the literature, I interrogate the assumptions underlying STEM workforce studies as it pertains to gender, race, class, and citizenship. First, I provide a brief overview of the pipeline model’s history and critiques. Next, I look at the contemporary use of the model in STEM workforce studies, focusing on the ways in which recruitment and retention, scientific work, and identity are represented, measured, and understood. I argue throughout that the pipeline model has a limited view of retention that is based upon socially constructed ideas about what constitutes “valid” scientific and engineering work and who counts as “real” scientists and engineers.