Electronic lab notebook (ELN)

An electronic lab notebook is the digital replacement for the paper lab notebook, where researchers document experiments, protocols, raw observations, and results as they happen, usually with timestamps, version history, and the ability to attach files, images, and instrument output directly to an entry.

Entries are typically organized by project or experiment and can be linked to samples tracked in a laboratory information management system. Where a LIMS centers on sample and workflow tracking, an ELN centers on the researcher's narrative and reasoning, closer to what a paper notebook recorded, but searchable, shareable, and far harder to lose or damage.

An ELN supports reproducibility and data provenance by creating a time-stamped, auditable record of what was actually done, which matters for patent disputes, regulatory submissions, and simply reconstructing a colleague's earlier work months or years later. It is a practical building block of good research data management. The pitfall is that an ELN only helps if entries are made promptly and completely; a notebook filled in after the fact, or one that pastes in final results without method detail, loses the auditability that is the entire point of keeping it.