The fields of science, technology, engineering, and mathematics, more ubiquitously known by the acronym “STEM,” have received a substantial amount of attention in recent years. As part of a research study investigating the alignment (or lack thereof) between the goals and priorities of educators and employers, we found it difficult to ascertain precisely what constituted a STEM occupation and to reconcile vastly different job, wage, and educational attainment projections. In this paper we explore the ways in which agencies and labor market researchers define STEM in six widely cited reports, and how these definitions influence the estimated and projected number of STEM jobs, estimates of how much these jobs pay, and what levels of education are necessary to attain these jobs. We find that agencies and researchers use different methods to classify STEM jobs (e.g., work tasks performed, knowledge, skills, education, type of work), which result in STEM job estimates ranging from 5.4 million to 26 million. Wage estimates exhibit a similarly wide range, from $50,000 to $96,000. In addition, jobs that require some STEM knowledge are frequently excluded from labor market analyses of STEM occupations, resulting in the under-counting of STEM-related jobs, the over-estimation of potential wages, and under-valuing of a sub-baccalaureate degree. Finally, we emphasize how groups of occupations (e.g., STEM) and industries (e.g., manufacturing) cannot be conflated with specific occupations. We recommend that researchers and agencies adopt a universal definition of STEM occupations and/or be more precise when speaking about the labor market in STEM related fields.