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How to Write the Discussion Section of a Psychology Lab Report
The discussion is where a lab report is won or lost. The results section tells the reader what happened. The discussion tells them what it means, and it is the part markers read most closely.
The most common mistake is repeating the results in longer sentences. A strong discussion does five separate jobs, in order. This guide shows each one with a worked example, then covers limitations, non-significant results and the mistakes that cost marks. For the rest of the report, see our APA 7 psychology lab report guide.
The five jobs of a discussion
| Order | Job | One-sentence formula |
|---|---|---|
| 1 | Answer the hypothesis | "As predicted / Contrary to the hypothesis, [group] [did what] compared with [group]." |
| 2 | Interpret the result | "This suggests that [explanation], although [what the design cannot show]." |
| 3 | Connect to earlier research | "This is consistent with / differs from [author, year], who found [finding]." |
| 4 | Explain the limitations that matter | "One limitation is [specific feature], which means [effect on conclusions]." |
| 5 | Say what comes next | "Future research could [specific change] to test whether [question]." End with one sentence on why the finding matters. |
Follow your course template for headings and length. Most rubrics reward the five jobs whether or not they are written as separate paragraphs.
Worked example
The data below are invented for illustration. Study: do students recall more words from a 20-word list after a 20-minute walk than after sitting quietly? There were 24 participants per group. Walking group: M = 14.2, SD = 2.8. Sitting group: M = 12.1, SD = 3.0. The result was t(46) = 2.51, p = .016, d = 0.72.
"As predicted, participants who walked for 20 minutes before the task recalled more words (M = 14.2, SD = 2.8) than participants who sat quietly (M = 12.1, SD = 3.0), t(46) = 2.51, p = .016, d = 0.72. The hypothesis was supported."
What this paragraph does: answers the hypothesis in the first two sentences and repeats only the numbers needed to anchor the claim. It does not re-present the full results.
"A difference of about two words on a 20-word list is a medium to large effect by conventional benchmarks. This suggests that a short walk may help encoding or retrieval, although this design cannot show which of the two was affected."
What this paragraph does: says what the result means and states what the design cannot show.
"This pattern is consistent with [Author, Year], who reported better recall after [what they did], and extends it to a [new feature of your study, for example a 20-minute walk]."
What this paragraph does: ties the result to the studies in your own introduction. Replace the brackets with real studies from your reading. Never cite a study you have not read.
"The sample was a convenience sample of undergraduate psychology students, so the result may not generalize to other groups. Mood and arousal were not measured, so it is unclear whether the walk improved recall directly or by lifting mood."
What this paragraph does: names two specific limitations and says what each one affects.
"A follow-up could test recall after a 24-hour delay and include a mood measure. If a short walk improves recall, simple breaks between study sessions may be a low-cost way to support learning."
What this paragraph does: proposes a specific next study, then closes with why the finding matters.
Limitations that earn marks
| Filler limitation | Specific version |
|---|---|
| "The sample size was small." | "With 24 participants per group, the study could reliably detect only large effects, about d = 0.8 or more, so a non-significant result would have been hard to interpret." |
| "There may have been human error." | "Testing took place at different times of day, which may have affected alertness and recall." |
| "Participants might not have been honest." | "Stress was measured by self-report, which may be affected by social desirability." |
| "More research is needed." | "A study with a 24-hour delay would show whether the effect lasts beyond the session." |
A good limitation names a feature of your study, says what it could change in the result, and does not apologize.
When your results are not significant
Do not write that the study "failed" or that the hypothesis was "disproved". Write: "The hypothesis was not supported." Then do the same four things as before.
- Report the direction of the difference, even if it was small.
- Check for a design reason: low power, a weak manipulation, an insensitive measure.
- Compare with earlier studies that did find an effect, and say how yours differed.
- Say what a stronger test would look like.
A clear, honest discussion of a null result scores as well as one for a significant result, because it shows you understand the design.
Mistakes markers circle
- Listing the results again instead of interpreting them.
- Using "proves" or "shows that" for a single study. Use "suggests" or "is consistent with".
- Introducing new data or new analyses.
- Never saying whether the hypothesis was supported.
- Making claims about causes in a correlational study.
- Confusing statistical significance with practical importance.
- Ending without a closing point.
Quick checklist
- Does the first paragraph say whether the hypothesis was supported?
- Is every claim tied to your results or to a study you cited?
- Are the limitations specific to your design?
- Is there one concrete suggestion for future research?
- Does it end with why the finding matters?
Frequently asked questions
How long should a discussion section be?
There is no universal length. Follow your rubric and word limit. A useful target is about one focused paragraph for each of the five jobs. You can check your total with our free word counter.
Can I use first person in the discussion?
APA 7 allows first person where it avoids awkward wording, for example "we found" for a group project. Your instructor's preference comes first, so check the course guidelines.
Can I add new results in the discussion?
No. Every number in the discussion must already appear in the results. The discussion interprets; it does not introduce.
What if my results are the opposite of my prediction?
Report them honestly, say the hypothesis was not supported, and discuss possible reasons using your design and the literature. Do not rewrite the hypothesis to match.
Is the discussion the same as the conclusion?
In APA style the discussion usually includes the closing points, and there is not a separate conclusion section. Some courses ask for a short conclusion, so check your template.
Related guides and tools
- How to write an APA 7 psychology lab report
- How to write a hypothesis for a psychology lab report
- Confounding vs extraneous variables in psychology
- Free word counter
- Psychology assignment help
Sources: American Psychological Association, Publication Manual of the American Psychological Association (7th ed.), and APA Style Journal Article Reporting Standards (apastyle.apa.org). Cohen, J. (1988). Statistical power analysis for the behavioral sciences (2nd ed.). Lawrence Erlbaum Associates.
Examples in this guide are illustrative. Check your course instructions and rubric before you submit.
