Communicating the logic of your reasoning is critical in science writing. Use your paragraphs to make your reasoning clear and explicit. Here is one useful heuristic for structuring your writing:

TOPIC SENTENCE —> EVIDENCE —> ANALYSIS —> CONCLUSION

Topic sentences help a reader navigate the ideas to form an argument with a paper. Topic sentences often do two things: they transition and they introduce.

  • A topic sentence helps communicate how a paragraph relates to the material that comes before it.

  • A topic sentence expresses the topic or claim of the current paragraph and, in doing so, provides some framing for the content of the paragraph.

Evidence comes from data you have collected or from source materials. You are presenting evidence when you are describing data collected by others, discussing previous findings, summarizing other’s theories or conclusions. In the introduction, the evidence is primarily material from previously published sources. In the discussion, the evidence is primarily the data and results of the current study, but you might also turn to material from previously published sources to support your interpretations of your data, consideration of limitations, and discussion of future directions.

Analysis comes in many forms. Often in science, we use statistics to help us evaluate hypotheses. However, there are other kinds of analysis beyond statistical data analysis, and those other kinds of analysis are likely reminiscent of what you learned in Expos. Analysis can involve comparing, explaining, applying frameworks, and evaluating theories. Analysis of your own data may incorporate the use of other sources. For example, when comparing your own findings to other sources, the act of evaluating the similarities and differences is analytical work. A data set cannot speak for itself, so we need both mathematical and conceptual tools to interpret it and relate it to what we know and to what remains to be discovered.

Conclusions help to advance an argument, by bringing the ideas expressed in a paragraph, or set of paragraphs, together meaningfully. This often occurs at the end of a paragraph or near the end of a set of paragraphs. The kind of concluding sentence used in a paragraph will depend on where the paragraph is in the paper: in the beginning of a paper, a concluding sentence may simply be identifying or highlighting something from the source or sources summarized in that paragraph; later in the paper, the concluding sentence may be arriving at a major conclusion of the paper’s argument. This component of the paragraph is fairly flexible, and if you are using a set of paragraphs together, the concluding sentence may show up at the end of the set.

NOTE:

This advice is a rule of thumb and should not be applied rigidly or without consideration of how it applies at a given moment within a paper. For example, in the beginning of a paper, you will often give background or provide a foundation on which to build. In these paragraphs, the content might primarily be evidence. You may choose to highlight something about that content or identify a pattern, but generally speaking, you may not engage in deep analysis or come to strong conclusions. Any analysis at the end of the paragraph is likely to be fairly modest.

Later in a paper, after you’ve had a chance to provide a summary of relevant sources or you’ve presented your data and results, then you are likely to get deeper into the analysis. Here the analysis is the conceptual exploration of either the literature you’ve reviewed or the study you’ve conducted.

Sometimes it might take more than one paragraph to make it through these four steps, in other words, to fully present a point your argument.