The Laboratory Notebook

Lab Notebook Purpose

Record keeping is an essential part of the scientific process. The laboratory notebook is the primary medium for these records, capturing the full range of activities crucial to effective science. It serves as a record of precisely what you did — both successfully and unsuccessfully — during the course of your experiment. It should capture the goals of the experiment, the procedures and approaches used, the analysis and modeling, and the results and interpretation. By reading a lab notebook, another scientist should be able to understand what experiment was conducted, examine the data, and follow the analysis and findings. It should contain enough information for another person to replicate the work.

Furthermore, notebook records are essential to corroborating anything that ultimately gets published. Effective record keeping is a skill that takes substantial time to develop, so it’s important to start early.

Important Information to Record

Researchers use lab notebooks to track a variety of information during daily lab activities — far more than just parameter values and data points. Most entries fall under one of four categories:

Objective information: The parameters, settings, and data that result from measurements, alignment, or other concrete actions. This is what you might commonly think of as scientific records — the “facts” of the experiment.

Subjective information: Your interpretation or evaluation of events in the lab, usually accompanying objective information. This is not “unscientific.” Researchers spend a great deal of time troubleshooting and redesigning apparatus to improve measurements. Including subjective impressions (e.g., “these data looked unusual” or “the alignment seems off”) helps you recall your assessment of prior measurements and put them in context.

Analysis information: Raw data analysis performed throughout the experimental process — short calculations, plots, and fits to models. Recording analysis alongside experimental details helps the reader interpret the results and compare them to theoretical predictions.

Planning information: Future plans or directions for the research, both short-term (e.g., retaking data with slightly different parameters) and long-term (e.g., a complete apparatus redesign). Because researchers constantly reflect on day-to-day outcomes, writing new ideas alongside other experimental information keeps them from getting lost.

Considerations When Recording Information

Context: Understanding “what did I measure and why did I measure it?” means understanding each entry in the broader picture of the entire experiment. When recording information, consider whether you can connect what you’re writing to the experiment as a whole. If you’re simply listing parameter values and data without explaining the reasoning behind your measurements, you’ll likely be unable to make sense of your notes later.

Audience: You are the primary audience, but authentic research is collaborative — lab records must be available to peers, advisors, and collaborators. When writing, imagine how others would interpret your entries. Keep in mind what you infer or assume without writing down, and ask yourself whether someone else could follow the context without that information. In your lab class, your audience also includes your lab partner and your instructor.

Timescale: You may need to reference notebook entries a week, a month, or (in a research setting) more than a year after recording them. You’ll never know in advance what you’ll need or when, but experience shows that some information is short-lived (e.g., equipment parameters updated in a few days) while other information is referenced for weeks or months (e.g., a commonly used alignment procedure). Ask yourself “when might I need this?” whenever writing something new. The farther in the future that may be, the more detail you should include.

Time investment: Keeping lab records is a balance between writing enough detail to be useful later and working efficiently enough not to stall your experiment. Record keeping is time intensive — most researchers feel they should be writing more, and very few feel they spend too much time on it. Treat record keeping not as an afterthought but as an integral part of the experimental process that will require substantial lab time to get right.

Examples

Lab Notebook Examples (PDF) — excerpts from a physics research lab here at CU Boulder. Several different researchers contributed entries, so you’ll see a range of styles and formats, but much of the same information and thought process appears in each. These excerpts illustrate authentic scientific record keeping and do not represent a definitive template for how you should maintain your own records.