Undergraduate students demonstrate common false scientific reasoning strategies

American education is failing to fill the growing demand for science, technology, engineering, and mathematics (STEM) graduates. The lack of critical reasoning skills may be a causal factor in student attrition from STEM majors. Our objective in this study was to discover and describe common false strategies used by undergraduate students during the scientific reasoning process. Each of these false strategies is described, with accompanying examples from student responses, to illustrate the thinking patterns. We defined targeted areas for instruction that can lead to better performance, greater academic self-confidence, and increased retention in STEM degrees. Understanding how students think through problems and where they are making mistakes facilitates the creation of specialized programs to correct these false reasoning strategies and increase the scientific reasoning ability of students.