How to Approach Writing a Lab Report

  1. Begin with the Materials and Methods section. This is a good section to begin with because it just involves detailing the steps that were taken in doing the experiment. Some things to remember when writing this section are that subheadings should be used for easy reference and that you should state the reason for doing something if it is not obvious.
  2. After the Materials and Methods section the Results section can be written. By writing the Materials and Methods section first, it is easier to order the Results section based on when data was collected. When writing the Results section keep in mind that the goal is to summarize the data. Therefore, things like how and why the experiment was formed and a discussion of the quality of the results and what they mean should not be present in the Results section. Any verbalization of the results should be a summary that draws attention to key points in figures. Therefore, it is best to create the figures first and then go back and verbalize the results.
  3. After writing the Results section the Discussion section can be written. Considering the fact that the Discussion section is an examination of the results in relation to expectations about how the experiment would turn out, it makes sense that this section can only be written after the Results section. In this section the expectations should be stated with supporting references and then the results of the experiment should be analyzed in relation to the expectations. Reasons for unexpected results should also be offered.
  4. After the bulk of the lab report has been written the student can go back and write the Introduction section. It is best to save this section for the end because the introduction gives an outline for the entire lab report in addition to giving background information about the topic. In -other words, the introduction outlines the issues that will be examined in the rest of the lab report and, because of this, it is easiest to save this section for near the end. While writing the introduction keep in mind that you should state the problem or question and then include factual details that are supported by references.
  5. After all the other sections have been written it is possible to write an Abstract. If an abstract is to be included it should be saved for last because an abstract summarizes in a single paragraph the content of the entire lab report. Therefore, it is easiest to write this section last after you know what the lab report contains. Keep in mind that abstracts are typically written in the passive voice and that they should be informative enough so that a reader can decide if it would be in their best interest to read the report after reading the abstract.
  6. After all the other sections have been written, a Reference section can be included based on what sources were used throughout the lab and a Title should be included. The specific format for references depends on the TA. Therefore, students should consult their TA for specific formatting instructions. Titles should be descriptive and give some insight into what your experiment was about specifically.

Guidelines for Lab Reports

  • Instructions for lab reports will vary slightly according to your professor and TA; make sure to follow the guidelines specific to your lab.
  • Lab reports are traditionally written in the third person; however, many biology courses today require that you use the first person for the sake of clarity. For example, “We measured the diameter of the pellet” as opposed to the passive ‘The diameter of the pellet was measured.” Always check with your professor or TA for his/her preference.
  • Should be a succinct, specific description that summarizes the experiment.
  • Single paragraph
  • Summarizes five key points, which are representative of the parts of a lab report:
    • why the experiment was conducted (introduction)
    • the problem being addressed (introduction)
    • what methods were used to solve the problem (materials/methods)
    • the major results obtained (results)
    • the overall conclusion from the experiment as a whole (discussion)
  • Tips: The abstract is brief, it is comprehensive but as efficient as possible. Five or six sentences should suffice. Write it last, using the rest of your report as a base from which you can condense the salient points into an extremely concise summary of the entire lab report.
  • Outlines the purpose of the experiment
  • Asks the question: why is the study important?
  • Uses background information to validate and expand on the importance
  • Tips: Depending on the course level, the introduction can be rather lengthy. There is often an extensive amount of background research involved; one of the main purposes of the introduction is to really show your TA/professor that you understand the implications and consequences of the experiment, and you’re expected to do this through your background research. See Works Cited.
Method and Materials
  • Detailed step–by-step account of the procedure
  • Tips: This part of the report is often hard to gauge; a general rule of thumb is to include enough detail so that a fellow biologist could exactly replicate the experiment. There should be no extraneous or subjective detail. Depending on your guidelines, the materials/methods section can often be presented as a bulleted list.
  • Systematic presentation of data; includes all relevant findings that contribute to the final conclusion
  • Data is presented in whatever form is most appropriate, such as graphs, figures, tables, etc.
  • Each set of data is numbered (Figure 1, etc.), labeled, and followed by a short explanatory paragraph
  • Tips: This is not a discussion of the experiment; it is an objective layout of your data. There should be no analysis of the results.
  • Interpretation of results: What did the experiment demonstrate?
  • Compare and contrast expected findings with actual findings
  • Explanation of unexpected results
  • Tips: Your results never “prove” anything; they only ever “support” the hypothesis. Be careful with scientific vocabulary. The discussion section, like the introduction, is another crucial place to demonstrate your grasp of the material; it’s important to be thorough, but equally important to avoid excessive or irrelevant information.
References/Works Cited
  • Alphabetical list of sources used
  • Tips: Whether or not you even have a works cited/references section depends, once again, on the level of the biology course. In upper level courses you are often required to have several outside sources, which provide the background information found in the introduction. These sources are usually from scientific journals; see below for two sample citations.

Bayne, B. L. 1972. Some effects of stress in the adult on the larval development of Mytilus edulis. Nature (London) 237: 459.

Carlton, J. T., G. J. Venneij, D. R. Lindberg, D. A. Carlton, and E. C. Dudley. 1991. The first historical extinction of a marine invertebrate in an ocean basin. Bioi. Bull. 180: 72-80.

Kristen McClaran