To keep an engineering notebook, write a dated entry every day you work on a project: the project name, what you set out to do, what you did, sketches, test setups and raw results, and the decisions you made and why. Write in permanent form, in sequence, with no blank gaps. Sign and date each entry, and for important work have a colleague who understands it read, sign and date it as a witness. Your employer’s notebook policy comes first, because the rules vary by company.
By Coplain Team
Last updated
Step by step
Check your employer’s notebook policy — before your first entry, find out what your company requires. Some issue numbered bound notebooks from a central log, some use an electronic notebook system, and some leave it to each team. The policy usually says who owns the notebooks (normally the employer), how entries are witnessed, where finished books are stored and what to do when you leave. Where the policy is silent, the steps below are common good practice, not a legal standard.
Start every entry with a date and the project — write the full date and the project name or number at the top of each entry. If you work on two projects in a day, start a new entry for each. A reader years later should be able to find every page about one project without reading the whole book, so keep a running index or table of contents at the front.
Record what you did, as you did it — write the objective, the method, the setup and the raw results while the work is happening, not at the end of the week. Record instrument IDs, part and revision numbers, material lots and settings, so the work could be repeated. Write down unexpected results and failed tests too; they are often the most useful pages later. If a measurement depends on a gauge, note its ID and calibration status, the same habit a calibration log supports.
Sketch, then attach what does not fit — draw sketches and test setups directly on the page and label them. Printouts, photos and plots that are too large go on a page, are signed and dated across the edge so removal would show, or are filed elsewhere with a reference in the notebook. In a digital notebook, attach the original file rather than a screenshot of it.
Write down decisions and the reason for them — when you choose a material, reject a design or change a tolerance, write the decision, the options you considered and why you picked one. If the decision changes a released drawing or document, the notebook entry is the thinking, and the formal change still goes through an engineering change notice.
Sign, date and have important entries witnessed — sign and date each entry when you finish it. For work that may matter later, such as a new idea, a key test result or a design decision, ask a colleague who understands the work but did not do it to read the entry, then sign and date it with a note such as “read and understood”. Do this promptly, not months later.
Close out and store finished notebooks — when a book is full or a project ends, complete the index, cross out unused pages and return or archive the book as your policy says. List it in the same place you track other controlled records, for example a master document list, so it can be found when someone needs it.
What an engineering notebook is for
An engineering notebook is a running, dated record of your technical work. It answers questions that come up long after the work is done: what did we test, with what setup, what did we see, and why did we choose this design? It helps the next engineer on the project, it helps you rebuild your own reasoning, and it supports formal records such as test reports and change notices.
Research organizations publish similar guidance for lab notebooks. The NIH Office of Intramural Research’s record keeping checklist, for example, asks that records be dated, legible, organized, timely, complete and backed up, and that they say what was done, when, why, how, by whom and as part of which project. Those questions are a good test for an engineering entry too.
Why entries are signed, dated and witnessed
A signature says who wrote the entry. A date says when. A witness signature says that someone else saw the entry at that time and understood it. Together they make the record harder to dispute and easier to trust, which is why many companies require them for research and development work.
The patent context has changed, so be careful with older advice. The USPTO’s America Invents Act FAQ explains that the first-inventor-to-file provisions took effect on March 16, 2013, and that for applications under those provisions the date of invention is irrelevant. The AIA also created derivation proceedings, which ask whether an inventor named in an earlier application derived the invention from an inventor named in the petitioner’s application. Whether and how your notebook matters in any of this is a question for your employer’s patent counsel, not for a blog post. This article is not legal advice.
Bound paper notebooks vs digital notebooks
A bound notebook with numbered pages makes gaps and removed pages obvious, needs no software and is easy to hand to a witness. Its weaknesses are search, backup and attaching data files. A digital notebook is searchable, can hold original data files and can be backed up, but its trustworthiness depends on the system: who can edit an entry, whether edits are tracked and how signatures are applied. A PDF export can be stamped with a watermark such as “CONTROLLED COPY” before it is shared.
Choose whichever your employer supports. If you have a choice, ask how each option handles four things: sequence (can entries be inserted or reordered), corrections (are changes visible), signatures (who signed and when) and retention (where it lives in ten years).
Electronic notebook system: search, attachments, audit trail if configured; depends on access control.
Digital planner or tablet notes: convenient and searchable; check whether your employer accepts it as a record.
How to make corrections
Never erase, white out or tear out a page. Draw a single line through the error so it stays readable, write the correction next to it, and initial and date the change. In a digital system, use its correction or amendment feature rather than overwriting text. The same rule runs through good document revision control: the history is part of the record.
Worked examples
Example: Example: one notebook entry for a fictional bracket redesign
Header: 2027-03-08 · Project BR-114, mounting bracket redesign · page 37 (all names and numbers invented for illustration).
Objective: check whether a 3 mm gusset stops the cracking seen at the weld toe on the current bracket.
Setup: sketch of the fixture with load point and strain gauge positions; test rig ID TR-02; gauge IDs SG-11 and SG-12; bracket drawing BR-114 rev C with a hand-added gusset.
Results: raw readings copied in a small table, with the plot printed, taped to page 38 and signed across the edge.
Decision: keep the gusset and change its thickness from 3 mm to 4 mm because readings at SG-12 stayed high; the change will go through an ECN.
Next step: make two 4 mm samples and repeat the test.
Signatures: author signed and dated 2027-03-08; witness, a test technician who watched the run, wrote “read and understood”, signed and dated 2027-03-09.
Result: A reader can tell what was tested, on which rig and drawing revision, what was seen, what was decided and why, and who saw it and when, without asking the author.
Common mistakes
Writing entries up at the end of the week from memory. Write while the work happens. A short, timely entry beats a tidy, late one.
Leaving blank pages or half pages between entries. Write in sequence and cross out any space you will not use.
Erasing or tearing out mistakes. Strike through once, write the correction, initial and date it.
Recording conclusions but not the raw data. Copy or attach the raw readings, setup and instrument IDs so the work can be repeated.
Asking a co-worker on the same task to witness, months later. Ask someone who understands the work but did not do it, and ask promptly.
Keeping project notes in several places. Use one notebook per project or one indexed notebook, and reference other files from it.
Frequently asked questions
What should an engineering notebook entry include?
The date, the project, the objective, the method and setup, the raw results, sketches, decisions with their reasons, the next step, and your signature. Add a witness signature for important entries.
Does an engineering notebook have to be witnessed?
It depends on your employer. Many companies ask for witness signatures on research and development entries. Follow your company’s policy and ask its patent or legal team if you are unsure.
Can I keep an engineering notebook on a tablet?
You can keep personal working notes on a tablet, but check whether your employer accepts that format as an official record. Some require a bound notebook or a specific electronic notebook system.
Who owns my engineering notebook?
Usually your employer, under your employment agreement and company policy. Read both, and do not take notebooks with you when you leave unless the company says you may.
Is a notebook still useful after first-to-file?
Yes. Beyond patents, it records tests, decisions and reasoning that the next engineer, an auditor or you will need. How it matters legally is a question for your employer’s patent counsel.