STEM Careers and Pathways: What Scientists Actually Do
A biochemist at the National Institutes of Health spends six hours on a Tuesday troubleshooting why a protein assay keeps producing inconsistent results. A climate modeler at NOAA writes Python scripts to process satellite data. A forensic geologist testifies in a federal courtroom. These are STEM careers — specific, varied, and nothing like the stock-photo image of someone in a white lab coat staring thoughtfully at a beaker. This page maps the actual scope of scientific work, how career pathways function, and where the real decision points lie.
Definition and scope
STEM careers span positions in science, technology, engineering, and mathematics — a category broad enough to include marine biologists, aerospace engineers, epidemiologists, data scientists, and nuclear physicists under one umbrella. The U.S. Bureau of Labor Statistics (BLS Occupational Outlook Handbook) tracks more than 100 distinct STEM occupations across federal classification codes, ranging from agricultural scientists to zoologists.
The scope matters because "STEM career" is often treated as a monolith when it is actually four overlapping domains with their own hiring pipelines, credential requirements, and workplace cultures. A software engineer at a biotech firm and a research chemist at a university both qualify statistically, but they inhabit almost entirely different professional worlds.
The /index for this site situates scientific work within a broader framework — the systems of knowledge, methodology, and application that make careers in science coherent rather than just a collection of jobs. Understanding what scientists do is inseparable from understanding how science works as a conceptual enterprise.
How it works
Most STEM careers operate along one of three structural tracks: research, applied/industry, and public sector. Each has a distinct logic.
Research track careers — found at universities, national laboratories (think Argonne, Oak Ridge, or the Jet Propulsion Laboratory), and research institutes — are organized around the production of new knowledge. Advancement depends heavily on peer-reviewed publication, grant acquisition, and citation metrics. The National Science Foundation (NSF) funds roughly $9.5 billion annually in basic research, and much of that money flows through academic labs employing graduate students, postdoctoral researchers, and principal investigators.
Applied/industry track careers convert existing knowledge into products, services, or processes. A materials scientist at a semiconductor firm, for instance, is not asking "what is this material?" but "how do we make this material behave reliably at scale, at speed, and under these specific thermal conditions?" The timeline pressure is different, the publishing expectation is minimal, and intellectual property agreements frequently govern what can be disclosed publicly.
Public sector track careers sit inside government agencies — the EPA, CDC, USGS, NASA, NIST — and focus on regulation, monitoring, standard-setting, and public service. A toxicologist at the Environmental Protection Agency (EPA) may spend years building the evidentiary record for a single chemical risk assessment rather than pivoting between projects every quarter.
A numbered breakdown of how a typical research career progresses:
- Undergraduate degree — establishes foundational discipline literacy; often includes a research internship or lab rotation
- Graduate training — master's (2 years typical) or doctoral program (4–7 years in most natural sciences); produces the dissertation and first publications
- Postdoctoral fellowship — 2–4 years of specialized research under a senior investigator; considered essential for academic positions in biology, chemistry, and physics
- Independent position — tenure-track faculty, staff scientist at a national lab, or senior researcher in industry
Common scenarios
The postdoc-to-faculty bottleneck is one of the most documented structural tensions in STEM. The National Academies of Sciences, Engineering, and Medicine (NASEM) published findings in its 2019 report The Science of Effective Mentorship in STEMM noting that graduate programs produce significantly more PhDs than tenure-track positions can absorb — a structural mismatch that has pushed PhD holders into industry and government roles at increasing rates.
Outside academia, the entry points look different. Engineers often enter industry directly after a bachelor's degree, with the master's pursued later (sometimes employer-sponsored). Data scientists working in genomics or climate research may hold doctorates or may not — the field is permissive in ways that molecular biology is not.
Interdisciplinary roles are increasingly common. Computational biologists occupy a space that neither traditional biology departments nor computer science departments fully claimed when the discipline emerged, and that ambiguity has become a structural feature rather than a temporary gap.
Decision boundaries
The fork between research and applied careers is sharpest at the doctoral level. A chemistry PhD who spends three postdoctoral years publishing in Journal of the American Chemical Society is building credentials for an academic position. The same person who takes an industry role immediately after the PhD is building a different kind of track record — one that may make returning to academia difficult, though not impossible.
Contrast this with engineering, where a licensed Professional Engineer (PE) credential — administered through the National Council of Examiners for Engineering and Surveying — carries weight across sectors. The PE exam creates a credentialing bridge that some sciences lack, making professional mobility more structured.
Geographic concentration is another real constraint. Particle physicists work where particle accelerators are. Marine ecologists work near coastlines or at institutions with ocean research programs. Unlike fields where remote work is neutral, much of experimental science is physically tethered to equipment and specimens that cannot be digitized.
The decision about whether to pursue graduate training, and in which form, is consequential enough that the careers in the science section addresses it in dedicated depth — including credential pathways, funding structures, and sector-specific hiring norms.