E. Discussion

This is where you interpret your results for the reader. It is the most important part of your paper and often one of the most difficult to write; be sure to allow enough time to work on it. The question, purpose (biological rationale) and hypothesis statements from the Introduction should guide the organization of the Discussion. Be specific. The following is not an appropriate conclusion: "The results were pretty much what we expected (see Results section)." State specifically what you conclude and the specific reason(s) for that conclusion. The Discussion should formulate and support a logical argument, leading the reader through the specific conclusions drawn from the data to their more general implications beyond the experiment.

Key elements in the Discussion Section:

• Support or reject hypothesis: State your conclusion(s) clearly in the opening paragraph. Restate your hypothesis and whether you support or reject your hypothesis referencing appropriate data. (Note that finding no difference between two treatments is still a conclusion). Be careful of your wording here. You cannot “prove” your hypothesis correct. Science cannot prove anything. Without getting into too much philosophical detail, the role of science is not to find proof, but rather to move closer to truth by disproving what is not true. Therefore, you will not be ‘proving your hypothesis’, but rather supporting or rejecting your hypothesis given the construct of your experiment and the data you have gathered.

• Formulate a logical argument: Explain the trends you feel are important to support your conclusion(s) and state your assumptions. Guide your readers through the steps in your reasoning referring back to your biological rationale to provide context. Present the arguments that explain how your experimental approach and the pieces of evidence (data) convinced you of your conclusion. For experiments where you carried out a literature search, compare your findings with information from the literature, citing appropriate references, thereby providing further support for your results-- or perhaps your results are contrary to others and you need to speculate the reasons for this difference. (These references include many that you cited in your Introduction section.) How do your findings add to those that others have observed? Are your results consistent or inconsistent with others findings—why or why not?

• Evaluate your experimental design: Evaluate the strengths and weakness of your experiment and your confidence (or lack) in your experimental design. Explain how these factors allow you to gauge the strength of your conclusion(s). Always address whether your protocol allowed you to truly test your hypothesis. In some cases you may discover unexpected inaccuracies in your data or that the methods you used were not appropriate or precise enough to address your question or test your hypothesis. Address the errors, unresolved issues and speculate how the experimental approach might be improved. Inconclusive results may show that you weren't asking a relevant question in the first place or that the experiment was not able to test the question you posed. This, in turn, can generate specific new questions and experimental approaches. Avoid making a laundry list of mistakes you made in carrying out your experiment. Only mention errors if they help explain unexpected data values and/or lead you to conclude that your methods did not allow you to test your hypothesis.

• Evaluate reliability of data: Once you have established that your experimental design was appropriate to address your original question, you must also evaluate your data reliability. How good are your data? Consider the variability in your data (variance, standard deviation, standard error). Did you have enough replicates? Did you have a large degree of experimental error? What are the implications of variability? Do not over-interpret your data. Recognize the magnitude of the variation within your data and the level of departure you would need to conclude true differences. In most cases you are trying to attach meaning to a group of numbers generated by some procedure. Help your readers make sense of these numbers by explaining how the patterns and relationships you observed reflect the biological concepts or issues you set out to explore. How do your data fit with your biological rationale?

• Implications of your results: How does your experiment add to the current body of knowledge? Speculate on the implications of your findings. It is essential that you refer back to your biological rationale. Implications are specific, reasonable extensions of your results or the meaning of your results for the larger picture. Be careful, however, with your choice of words: state implications as logical possibilities rather than as fact. Your results may lead to new insights about relationships in nature. An unexpected result (if it holds up on repeating the experiment) may yield insight to guide a more effective experimental approach.

• Next Steps: Science is built on an iterative cycle of questions, experiments, results and conclusions. Often it is appropriate to suggest the next step in the investigation. Be sure to include the reasoning that lead to your insights. They may be speculative, but they should be well-reasoned. Your experiment will likely provide many opportunities to ask new questions.

• Final Conclusion: End your paper strongly with a clear, brief conclusion that relates directly to the question, hypothesis, or problem you stated in the Introduction.

If you get stuck:
The hard work of making meaning of data will be easier if you have a clear idea of what it was that you set out to do in the first place. Re-read your question and biological rationale (purpose) statements. Do your results allow you to answer the question you posed in your statement? Do you understand your data? If not, re-read the lab manual. A second reading after examining your data will often solve much of the confusion you may be experiencing. Be sure to discuss your results thoroughly with your research team. They may have some insight, intriguing literature for comparison, or thoughts about the data that could benefit your interpretation.

Other things you can do:

• Take a look at the example of a good discussion on the next page.
• Make a concept map. This is especially useful for seeing new connections, structuring ideas, and finding interactions at multiple levels.
• Explain the experiment and its significance to a friend who knows nothing about it. If you understand the full content, context, results and relevance of your experiment, you should be able to explain what was done and what it means. This should help provide some organization to your paper.

Example of good discussion sections

How will discussions be evaluated? The following is part of the rubric we will be using to evaluate your papers. Example Discussion on the next page.