Purpose
What does a lab report conclusion do?
The conclusion states what the investigation demonstrated. It answers the research question and summarizes the evidence that supports the final scientific statement.
A conclusion should not repeat the entire report. It should select the most important finding and explain how that finding relates to the objective or hypothesis.
Recommended structure
Four parts of a strong conclusion
- Restate the investigation purpose
- Answer the research question directly
- Support the answer with key evidence
- Evaluate the hypothesis
Direct answer
Answer the research question
Begin with the main relationship, comparison, or outcome established by the investigation. Use clear language and avoid vague statements such as “the experiment worked.”
Direct conclusion statementIncreasing solution temperature decreased reaction time and therefore increased the reaction rate.
Supporting evidence
Include the most important result
Support the conclusion with selected numerical or observational evidence. Use only the values needed to demonstrate the main finding.
Weak conclusion
Unsupported statement
Higher temperature made the reaction faster.
Strong conclusion
Evidence-based statement
Reaction time decreased from 84 seconds at 20°C to 31 seconds at 50°C.
Hypothesis
State whether the evidence supported the prediction
Explain whether the results supported, partially supported, or did not support the hypothesis. Avoid saying that the hypothesis was proven because one investigation rarely establishes absolute certainty.
Hypothesis evaluationThe hypothesis was supported because the measured reaction time decreased consistently as temperature increased.
Important distinction
Conclusion versus discussion
Discussion
Detailed interpretation
- Scientific explanation
- Anomalies
- Limitations
- Uncertainty
- Improvements
Conclusion
Final scientific answer
- Main finding
- Research-question answer
- Key evidence
- Hypothesis evaluation
Scope
Keep limitations brief
Detailed evaluation belongs in the discussion. Mention a limitation in the conclusion only when it directly changes how confidently the final answer can be stated.
For example, a small sample size may mean the observed relationship should not be generalized beyond the tested conditions.
Writing framework
Lab report conclusion structure
Purpose
This investigation examined whether...
Main finding
The results showed that...
Evidence
This was demonstrated by...
Hypothesis
Therefore, the hypothesis was...
Common mistakes
Conclusion problems to avoid
- Introducing new results.
- Repeating the complete discussion.
- Making claims without evidence.
- Saying that the hypothesis was proven.
- Using vague statements about success.
- Ignoring the research question.
- Adding unrelated scientific information.
Related guides
Review the evidence before concluding
Review the interpretation and limitations in the Lab Report Discussion guide, or review the complete report structure in the Lab Report Format guide.
Questions and answers
Lab report conclusion FAQ
What should a lab report conclusion include?
A conclusion should answer the research question, summarize the main finding, cite important evidence, and state whether the hypothesis was supported.
How long should a lab report conclusion be?
It should be concise while still presenting the main finding and supporting evidence. Its exact length depends on the investigation and assignment requirements.
Should limitations appear in the conclusion?
Detailed limitations normally belong in the discussion. A major limitation may be mentioned briefly only when it directly affects confidence in the conclusion.
Can new results be added in the conclusion?
No. The conclusion should synthesize evidence already presented in the results and discussion rather than introduce new data.