I recently underwent an undergraduate research experience that depended significantly on the legible and comprehensive work detailed in the notebook of a previous researcher in order to continue their efforts. From the wide range of data collected over the course of the project, it made the biggest impression to me and other participating students to observe and adopt the formatting techniques of the more organized notebooks based on a simple rationale — they were the easiest to maneuver and dissect information from when the time came to apply their use. Data tables, figures, labelled visuals, calculations and proficiency in written expression — each contributed to the importance of understanding how the experiment(s) were carried out and the possibilities of improving the methods.

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(https://dominidaiyz.wordpress.com/2017/05/05/why-lab-notebook-entry-format-matters/)