What Makes STEM Writing Different From Other Academic Writing
If you’ve written high-school essays or humanities papers, you already know the kind of writing that values interpretation, argument, and rhetorical flourish. STEM writing is fundamentally different.
According to the Hamilton College Writing Center, scientific writing rests on three core principles: precision, clarity, and economy. Every sentence should do one clear job. Metaphor, personal commentary, and decorative language have no place in lab reports or technical papers — not because they’re forbidden by some arbitrary rule, but because they obscure the data your reader came to see.
- The IMRaD structure (Introduction, Methods, Results, Discussion) follows an “hourglass” pattern: broad-to-narrow in the Introduction, narrow data at the center, narrow-to-broad in the Discussion
- STEM writing rests on three principles from Hamilton College: precision, clarity, and economy — every word should earn its place
- “Data” is plural in scientific writing. “The data show” is correct; “the data shows” is wrong — a mistake that trips up nearly every STEM student
- Never write the abstract first. It’s the single most common structural error students make
- Science never “proves” hypotheses — it supports, suggests, or fails to support them. Using “proved” is a common grading penalty
Here is a quick comparison of how the same idea looks across disciplines:
| Feature |
STEM Writing |
Humanities Writing |
| Primary goal |
Reporting findings, testing hypotheses |
Interpretation, critical argument |
| Tone |
Objective, impersonal, direct |
Interpretive, persuasive, analytical |
| Voice |
Traditionally passive or team-focused; active voice increasingly accepted for clarity |
Active voice preferred; first-person common |
| Pronouns |
Minimized or avoided; “we” for research team |
Frequently used to position argument |
| Metaphor |
Avoided |
Common and appropriate |
| Sentence length |
Short, direct, concise |
Longer, more complex |
The goal in STEM writing is not to persuade through rhetoric. It is to report findings so clearly that another researcher could duplicate your work. The University of Southampton’s English for Engineers guide emphasizes that a good lab report should let a reader replicate your experiment using only what is written.
For a deeper exploration of tone differences across disciplines, see our Academic Writing Tone: Discipline-Specific Examples (STEM vs Humanities).
The IMRaD Structure Across STEM Disciplines: The “Hourglass” Metaphor
The IMRaD framework — Introduction, Methods, Results, Discussion — is the standard structure for lab reports and research papers across biology, chemistry, physics, engineering, and computer science. While details vary by field, the core architecture is consistent.
Understanding the IMRaD structure as an hourglass shape — not just a list of sections — is one of the most powerful mental models you can use. This geometric metaphor, taught consistently by university writing centers including Hamilton College, Trent University, and Sheffield, explains why each section is structured the way it is.
The Top of the Hourglass: Introduction (Broad → Narrow)
The Introduction starts at the wide end of the hourglass. You begin with the general context of your field and gradually narrow toward the specific experiment you performed.
What the Introduction should do:
- Provide background context (the broad field)
- Review relevant literature (what others have done)
- State the specific problem or question
- State your hypothesis or research objective
- End with a clear statement of purpose
Think of it as an inverted funnel. Each paragraph narrows the focus until the last paragraph states exactly what your experiment was designed to test.
What the Introduction should NOT do:
- Launch into a grandiose statement like “Since the beginning of time, scientists have studied…” — the Vanderbilt Writing Resources explicitly identifies this “march of history” opening as a common student error.
- Present results or data. That belongs in the Results section.
- Go into procedural detail. That belongs in the Methods section.
The Narrow Center: Methods and Results
The neck of the hourglass is the narrowest part — specific, concrete, discipline-specific data. This is where you report exactly what you did and what you found. No interpretation yet. Just the raw facts.
Methods (experimental procedure):
- Document every step clearly enough that another student could replicate your experiment
- Include equipment specifications, sample sizes, measurement intervals, environmental conditions
- Use past tense: “The solution was heated to 95°C for 10 minutes”
Results:
- Present data clearly using tables, figures, and statistical summaries
- Do not interpret or discuss the results here — saving that for the Discussion
- Reference each figure and table in the text before or alongside it
The Bottom of the Hourglass: Discussion (Narrow → Broad)
The Discussion section widens out from the narrow center. You start with your specific findings and gradually expand to broader implications.
What the Discussion should do:
- Interpret what the results mean
- Compare your findings with existing literature
- Discuss limitations and sources of error
- Connect your specific results to the broader context introduced in the Introduction
The Vanderbilt Writing Resources identifies the Discussion as “the most important part” of a lab report. This is where you answer the question: “So what?”
What the Discussion should NOT do:
- Introduce new results you haven’t reported in the Results section
- Overgeneralize beyond your data’s scope
- Make claims not supported by your actual findings
Tense Conventions by Section
Verb tense is one of the most inconsistent areas in student writing. The University of Southampton’s English for Engineers guide provides the most detailed tense-by-section table available, and here it is in full:
| Section |
Verb Tense |
Example |
| Abstract |
Present (for aims, permanent states) and Past (for what was done) |
“This study investigates…” / “Samples were collected…” |
| Introduction |
Present (for aims, background facts, permanent states) and Past (for previous experiments) |
“X is known to affect…” / “Previous studies showed…” |
| Methods |
Past |
“We measured the absorbance at 450 nm every 30 seconds.” |
| Results |
Past (for what you found) and Present (for explaining figures) |
“The reaction rate increased.” / “Figure 1 shows the temperature profile.” |
| Discussion |
Present (for interpretations, general truths), Past (for specific results), Modals (for cautious claims) |
“These results suggest…” / “Our data indicated…” / “This may indicate…” |
Using the wrong tense is flagged by Southampton as one of the three most common student writing errors. Consistent tense usage signals that you understand the distinction between what you did (past) and what your findings mean (present).
Discipline-Specific Variations
While IMRaD is the universal framework, each STEM discipline has its own nuances. Understanding these differences is essential for writing a report your professor will actually understand.
Biology: Hypothesis-Driven and Literature-Centric
Biology lab reports tend to be hypothesis-driven. You state a clear prediction and then test it. Literature citations are central — your Introduction should connect your experiment to established biological theory.
Key features:
- Emphasis on experimental design and control groups
- Detailed statistical analysis (t-tests, ANOVA, Chi-square)
- % error calculations common
- Strong focus on biological significance (not just statistical significance)
Citation style: Biology typically uses name-year formats (CSE Name-Year or Harvard). In-text citations look like (Smith 2020) or Smith (2020) argued that…. See our CSE Citation Style Guide for detailed CSE formatting rules.
Chemistry: Quantitative and Stoichiometric
Chemistry lab reports are heavily quantitative. You calculate yields, reaction rates, molarities, and percent errors. The report documents not just what happened, but the precise numbers that describe it.
Key features:
- Stoichiometry calculations and reaction equations
- Percent error and yield calculations
- Detailed procedural descriptions with measurements
- Strong focus on accuracy and precision
Citation style: Chemistry typically uses numbered citation styles (Citation-Sequence). A superscript number in the text refers to a numbered reference list. See our Vancouver Citation Style Guide for this numbering-based system.
Physics: Mathematical Models and Uncertainty
Physics lab reports emphasize mathematical modeling and uncertainty analysis. You derive equations, compare theoretical predictions with experimental data, and quantify measurement uncertainty.
Key features:
- Derivation of theoretical equations
- Uncertainty propagation (how measurement errors compound)
- Graphical analysis with error bars
- Strong emphasis on SI units and dimensional consistency
Citation style: Physics often uses numbered citation for equations and references. See our guide on CSE Citation Style Guide for details on citation systems used across STEM fields.
Engineering: Goal-Oriented and Design-Focused
Engineering reports are goal-oriented. You define a problem, develop a solution, test it, and draw conclusions about whether it meets specifications.
Key features:
- Problem definition and objectives upfront
- Design alternatives and evaluation criteria
- Cost-benefit analysis (when applicable)
- Strong emphasis on practical implications
Engineering technical reports follow a broader structure than pure lab reports — they may include executive summaries, appendices with raw data, and detailed schematics. See our Technical Report for Engineering Students for a comprehensive guide to engineering-specific formats.
Computer Science: Algorithm Analysis and Experimental Comparison
Computer Science lab reports blend mathematical analysis with experimental comparison. You may implement an algorithm, measure its performance, and compare it against established benchmarks.
Key features:
- Algorithm complexity analysis (Big-O notation)
- Benchmark comparisons and runtime measurements
- Experimental configurations and parameter settings
- Strong emphasis on reproducibility
Citation style: Computer Science often uses IEEE-style numbered citations, though some programs prefer APA-style name-year formats. Check your course requirements.
Technical Communication Best Practices in STEM
Good technical communication in STEM is not just about structure. It’s about how you choose your words, organize your data, and present your findings to an audience that values precision over flair.
Precision: Use the Right Words
“Precision” means using exact terminology. Don’t say “the substance changed color.” Say “the solution turned from clear to pale yellow.” Don’t say “a large number of samples.” Say “34 samples.” Don’t say “statistically significant” without reporting the p-value or confidence interval.
Concision: Say It in Fewer Words
“Clarity” and “economy” go hand in hand. If you can say it in one sentence, don’t use three. Cut filler phrases like “it is important to note that,” “in order to,” or “it can be argued that.” STEM readers are busy. They want your findings, not your padding.
Objective Tone
The Hamilton College guide emphasizes that scientific writing should maintain an objective tone. Your findings speak for themselves — you don’t need to add commentary like “this is a remarkable result” or “unfortunately, the experiment failed.” Let the data carry the weight.
Note: For discipline-specific tone examples and a detailed STEM vs. humanities writing comparison, see our Academic Writing Tone: Discipline-Specific Examples (STEM vs Humanities).
Visual Data Integration
Tables, graphs, and figures are not optional extras in STEM writing — they are essential components. A well-designed figure can replace several paragraphs of explanation. Here are the standards:
- Table captions go above the table
- Figure captions go below the figure
- Every visual must be referenced in the text — never present a visual without saying “As shown in Figure 1…” or “Table 2 summarizes…”
- Avoid presenting the same data in both a table and a figure — choose one
- Do not include raw data in the main text — put raw measurements in an appendix; present summarized results in tables
Common Student Mistakes and How to Avoid Them
These mistakes appear in nearly every batch of student lab reports. They’re avoidable, and fixing them can raise a grade significantly.
Mistake 1: The “Proof Fallacy”
What students write: “I proved that X equals Y.”
What they should write: “The results support the hypothesis that X equals Y.” / “The data suggest a relationship between X and Y.”
Why it matters: Science never “proves” hypotheses. It supports them, suggests them, or fails to support them. The act of “proving” belongs to mathematics and logic, not to empirical science. This mistake appears consistently across university writing centers. The University of Regina biology lab guide specifically flags it as a major grading penalty.
Mistake 2: Attributing Everything to “Human Error”
What students write: “The unexpected results were caused by human error.”
What they should write: “The discrepancy likely stems from parallax error when reading the meniscus” or “Reaction time variability with the stopwatch may account for the 4% deviation.”
Why it matters: The University of Regina explicitly states that “human error” is the worst possible explanation. It’s vague, unhelpful, and tells your reader nothing. Identify the specific measurement limitation instead: parallax in reading a meniscus, reaction time with a stopwatch, temperature fluctuations, instrument calibration drift.
Mistake 3: The “March of History” Introduction
What students write: “Since the beginning of time, chemists have been studying chemical reactions.” / “Humans have always been curious about the natural world.”
What they should write: “Understanding reaction kinetics is essential for optimizing pharmaceutical synthesis. Previous studies have focused on…”
Why it matters: Vanderbilt Writing Resources identifies the “march of history” intro as a common student error. Lab report introductions should start directly with the specific problem and context — not with grandiose statements about human curiosity or centuries of scientific endeavor.
Mistake 4: Writing the Abstract First
What students do: They write the abstract before finishing the rest of the report.
What they should do: Write the body first (Methods, Results, Discussion), then the Introduction, then the Abstract — last.
Why it matters: Southampton identifies this as the single most common structural error. When you write the abstract first, you’re forced to guess at what your report contains. This often leads to unnecessary detail, or to information not found anywhere in the body. Writing the abstract last ensures it accurately reflects the completed work.
Mistake 5: “Data Is Singular”
What students write: “The data shows…” / “The data indicates…”
What they should write: “The data show…” / “The data indicate…”
Why it matters: “Data” is plural in Latin and in standard scientific English. “The data show” is correct. “The data shows” is incorrect. This subtle grammatical error is flagged by University of Regina as one of the most common mistakes among STEM students writing in English.
Mistake 6: Wrong Tense Usage
What students write: Mixing past and present tense within the same section.
What they should do: Follow the tense-by-section table above. Methods = past tense. Results = past tense for findings, present tense for explaining figures. Discussion = present tense for interpretation, past tense for reporting results.
Why it matters: Tense inconsistency signals that you’re not thinking about the distinction between what happened (past) and what your findings mean (present). Southampton lists tense errors as one of the three most common student mistakes.
Mistake 7: Personal Language in Technical Reports
What students write: “I think the experiment worked well.” / “In my opinion, the results were surprising.”
What they should write: “The results were consistent with expectations.” / “The deviation from predicted values suggests…”
Why it matters: Personal commentary and opinion language undermine objectivity. STEM writing should maintain an objective, third-person tone. If you want to express cautious interpretation, use hedging language: “suggests,” “indicates,” “may reflect.”
Visual and Data Presentation Standards
How you present your data matters as much as the data itself. Poor visual presentation can make excellent results look amateurish.
Table vs. Figure: When to Use Each
| Element |
Placement Rule |
| Tables |
Caption above the table |
| Figures/Graphs |
Caption below the figure |
| Every visual |
Must be referenced in the text before or alongside it |
Best Practices for Tables
- Include descriptive headers
- Report uncertainty alongside measured values (e.g., “4.23 ± 0.05 s”)
- Use SI units consistently
- Avoid presenting the same data in both a table and a figure — choose one
Best Practices for Figures
- Label axes with units (e.g., “Temperature (°C)”, not just “Temperature”)
- Include error bars where applicable
- Use clear, legible fonts and line widths
- Avoid presenting raw data in a figure — summarize or aggregate it first
- Color-blind friendly: avoid relying on color alone to distinguish data series
Don’t Do These
- Present raw data in the main body. Put raw measurements in an appendix and present summarized results in tables.
- Show the same data twice in different formats (both a table and a graph of the same numbers).
- Use figures without referencing them in the text. Every figure should say “As shown in Figure 1…” or “Figure 2 illustrates…”
- Skip uncertainty reporting. If you measured something, report the uncertainty. If you didn’t, you should have.
Citation Styles in STEM
Every STEM discipline expects a specific citation style. Using the wrong one is a common and preventable error.
IEEE (Engineering and Computer Science)
- Numbered system with superscript references:
...previous work[1].
- References ordered numerically by first appearance
- Widely used in engineering journals and conferences
- See our CSE Citation Style Guide for detailed formatting of citations across STEM disciplines
CSE (Biology and Life Sciences)
- Offers three systems: Name-Year, Citation-Sequence, Citation-Name
- Name-Year looks like
(Smith 2020) or Smith (2020)
- Citation-Sequence uses superscript numbers ordered by appearance
- See our CSE Citation Style Guide for detailed examples
Numbered Styles (Chemistry)
- Numbered references (superscript or bracketed)
- References ordered by first appearance in the text
- Often used in journals like Journal of the American Chemical Society
APA (Interdisciplinary and Social Sciences)
- Name-year format with comma:
(Smith, 2020)
- Common in education, healthcare, and interdisciplinary programs
- See our guide on APA 7th Edition Updates for formatting details
Rule of thumb: When in doubt, ask your instructor. Citation styles are rarely “free choice” — your professor or target journal determines which style is required.
A Practical Writing Workflow
Experienced researchers do not write lab reports in the order the sections appear. They follow a workflow that prevents the structural errors students constantly make.
Step 1: Draft the Body First
Write the Methods and Results sections first. These contain the substance of your report — what you did and what you found. They are the hardest part to fake or guess at.
Step 2: Write the Discussion
Now interpret your results. Compare them with expectations. Discuss limitations. This is where your analytical thinking shines.
Step 3: Draft the Introduction
Now that you know exactly what your report contains, write the Introduction. Frame the problem accurately based on what you actually did.
Step 4: Write the Abstract
With the entire report complete, write a concise 100–150 word summary. This ensures it accurately reflects the completed work.
Step 5: Add Visuals and References
Insert tables, figures, and citations. Ensure they’re numbered, referenced in the text, and formatted to your discipline’s standards.
Step 6: Proofread and Format
Check for consistency in tone, units, terminology, and citation style. Verify tense usage across sections. This is where you catch “human error,” “data shows,” and “march of history” mistakes.
Summary and Next Steps
Lab reports and technical documents in STEM follow a consistent framework — IMRaD structure, the hourglass pattern, discipline-specific nuances — but they also demand precision in word choice, tense usage, and data presentation. Understanding the conventions of your discipline is the difference between a lab report that reads like professional science and one that reads like a student trying to guess what’s expected.
Key takeaways:
- IMRaD follows an hourglass: broad → narrow in the Introduction, narrow → broad in the Discussion
- STEM writing rests on three pillars: precision, clarity, and economy
- Tense conventions are section-specific — follow the table above
- “Data” is plural; “the data show” is correct
- Never write the abstract first — always write it last
- Science “supports” hypotheses, never “proves” them
- Avoid “human error” as an explanation — identify specific measurement limitations instead
What We Recommend
When writing a lab report, the single most impactful workflow change you can make is: write the body first, then the Introduction, then the abstract last. This sequence prevents the structural errors that most students make — and it forces you to write accurately based on what you actually did, rather than guessing what your report will contain.
Second, let your data drive your argument. Don’t force conclusions before you’ve analyzed the results. If your findings contradict your hypothesis, report it honestly — that’s where genuine scientific thinking begins.
Third, be meticulous about tense. Check every verb against the tense-by-section table. It’s a small detail, but one that affects whether your writing reads as professional or amateurish.
Related Guides
For complementary resources to improve your academic writing:
Need Help With Your Lab Report?
If you’re struggling with structuring your lab report, formatting your data, or understanding discipline-specific conventions, our academic writing experts can help. We provide customized lab report writing and editing services tailored to your specific discipline and assignment requirements.
Get a free lab report review from our academic experts →
Frequently Asked Questions
Q: Can I use first-person pronouns (“I,” “we”) in a lab report?
A: Traditionally, STEM lab reports minimize first-person pronouns. Passive voice (“The solution was heated”) or team-focused language (“We heated the solution”) are preferred. However, active voice is increasingly accepted in Methods sections for clarity — especially when describing your team’s actions. Check your professor’s preference or your course’s style guide.
Q: Should I include raw data in my lab report?
A: No. Present summarized results in tables or figures. Put raw measurements in an appendix and reference it. Including raw data in the main body makes the report hard to read and wastes space.
Q: How long should a lab report be?
A: Lab report length varies by discipline and course requirements. A common range is 1,500–3,000 words for undergraduate reports. The key is substance over length — a focused, well-structured report outperforms a padded one every time.
Q: What’s the difference between a lab report and a research paper?
A: Lab reports document experiments you conducted as part of a course. Research papers document original research (often at the graduate level) and follow a similar IMRaD structure but with deeper literature review and more rigorous methodology. See our Research Paper Structure guide for details.
Q: How do I know if I’m using the right tense?
A: Follow the tense-by-section table above: past tense for Methods and Results (what you did), present tense for Discussion (what your findings mean), and a mix of present and past in the Introduction (background facts = present; previous experiments = past). When in doubt, ask your professor.
This guide covers lab report conventions across all major STEM disciplines. For discipline-specific tone conventions, see our Academic Writing Tone guide. For engineering report formats, see our Technical Report for Engineering Students guide.
