Lab reports typically document the process followed in a laboratory for an experiment. They are often written as class assignments. In a professional setting, lab reports may be used to provide a progress report to a research team or supervisor or to document research being conducted. When writing a lab report, consider audience and purpose so that you can decide how much detail to include and what to emphasize.

Lab reports usually follow a standardized format known as IMRaD (Introduction, Materials and Methods, Results, and Discussion). This format allows others to easily identify your methods and findings, to precisely replicate your experiment, and to accurately place your individual work within a larger body of research. However, some lab reports have specific requirements not covered by this format, so be sure to check your assignment or sample lab reports. These will demonstrate the appropriate citation style, verb tense, and other conventions you should follow.

Title and Abstract

A lab report requires a short, descriptive title. Use key words that will help an interested reader decide if the report meets their research needs.

An abstract consolidates a lab report into a readable format that describes the experiment. If your report requires an abstract, consider writing it after you write the main report. A good strategy is to include sentences, possibly simplified, from each of the IMRaD sections. Depending on the purpose of your lab, you may emphasize certain sections more than others. For example, if your lab is meant to teach about methods, you may devote more space to Materials and Methods in your abstract. If the lab focuses on the outcome of an experiment and what steps to take next, you’ll probably focus more on Results and Discussion. The abstract typically runs 100 to 250 words, but, again, check your assignment or refer to a sample report for specifics.

Introduction

The Introduction identifies the objective(s) of your lab report and provides context. It may include the following, depending on the purpose and audience:

• brief background regarding the purpose or objectives of the experiment: is it solving a problem or answering a question? Is it related to a larger study? The purpose usually addresses a large question, while the hypothesis narrows that down to something testable.
• the hypothesis: a statement of what the expected outcomes will be
• description of the experimental design—how you will answer the question or test the hypothesis

Materials and Methods

Materials and Methods (sometimes called Procedures) describes what was done in the lab including the materials used and step-by-step procedure(s) followed (Hofmann 247-8). This section should be precise, specific, and straightforward, so that others can replicate your experiment exactly. The level of detail you include depends on audience and purpose. If you are reporting to a team that is fully familiar with a particular procedure, you probably don’t have to describe it step-by-step. However, if you are introducing a new step, you need to be specific enough for others to replicate the procedure. Materials and Methods should include a description of the materials that were used and a description of the manner in which they were used.

Answering the following questions will help you flesh out this section:

• Does it make sense to describe your procedure chronologically?
• Should you omit information that is common knowledge in your field (e.g., the operation of a given apparatus or the use of a certain mathematical model)?
• Should you provide technical information about the materials used?
• Have you included those details and descriptions that are essential to the procedure (e.g., “we poured A into B” vs. “we poured A into B at a rate of C”)?
• Should you use passive voice (e.g., “the model was used”) or active voice (e.g., “we used the model”)?

Results

Results lists the outcome(s) of your experiment (and controls, if used). Limit Results to a description of your findings, since you will interpret these in the Discussion section, unless you have been instructed to consolidate Results and Discussion into one section. Following are some general guidelines for Results:

• Order your results chronologically or from most to least important (Hofmann 269).
• Do not simply present data (e.g., “the rates were compared”) but interpret it for the reader (e.g., “the rate increased by a factor of x, indicating y”) (Hofmann 266).
• Contextualize the data so that the reader understands its significance (e.g., “the rate increased by a factor of x, indicating y. This is consistent with our assumption z.”).
• Results may include visuals such as tables and figures. Label these appropriately (e.g., “Figure 1,” “Table 1”) and consistently.

Discussion

In the Discussion section, explain whether or not the objectives of your experiment, as identified in the Introduction, were fulfilled, or if the hypothesis was supported. This is an important section if you are writing to your research team or supervisor. They’ll want to know what you think of the results and how you see this particular experiment in the context of a larger research project. If you are writing to a class, this section can demonstrate to your instructor that you understand the principles being taught in the lab. Hoffman (290) suggests you include the following:

• a summary of your key findings
• your interpretation of key findings
• an explanation of any unexpected findings
• difficulties you encountered and how these might have been avoided
• errors you made and how to account for them
• recommendations for anyone attempting to replicate your experiment

Appendix

An appendix (or plural, appendices) is where you include information that’s important but too unwieldy or detailed for the main report. An appendix may, for example, include the instruction manual for an apparatus or a description of an industry standard you used in making a measurement. If it is relevant or interesting, but not essential for the main report’s reader, it might go in an appendix. If you include an appendix, label each item carefully so the reader knows what it is and how to find it.

Style

Strive for a direct, simple, and professional style that puts focus on the work, not on you as the person performing the work. Use full sentences and use paragraph breaks within sections to organize information logically and make it readable. Long chunks of text can be difficult to read.

Keep in mind these additional tips:

• Watch your verb tenses (i.e., past, present, future). If you are describing what you did, as in Materials and Methods, stick with past tense. In the Discussion section, you might use present tense to describe the current state of research and future tense to describe what further work remains to be done.
• If you use abbreviations that are uncommon or that may be unfamiliar to readers, use the full term the first time it’s mentioned, followed immediately by the abbreviation in parentheses.
• Follow abbreviations of metric units by a period.
• Precision is crucial. Instead of writing that something was “very hot,” give a temperature or temperature range. Instead of writing “the results were significant,” explain how you measure significance and report the results in that context.

References

Goldbort, Robert. Writing for Science. Yale University Press, 2006. Print.
Hofmann, Angelika H. Scientific Writing and Communication: Papers, Proposals, and Presentations. New York: Oxford University Press, 2010. Print.