Laboratory notebooks are often the documents that patentees attempt to rely upon to show the date of invention. The need to prove the date of invention can arise in a number of contexts. For example, the patentee may need to establish that the date of invention to overcome prior art that has been cited against a pending patent application or has been raised in litigation to invalidate the patent. The patentee can overcome some types of prior art by demonstrating that he invented before the date of the newly discovered art.

An applicant for patent or a patentee may need to prove that it invented first. In an interference, two entities are seeking to patent the same subject matter. The one who is first to invent is the one entitled to the patent. The one who reduced the invention to practice first is the first to invent, unless the other party conceived the invention first and diligently reduced the invention to practice. Thus, in an interference, the dates of conception and reduction to practice, as well as the efforts made in between to reduce the invention to practice are of key facts in determining who gets the patent.

Laboratory notebooks can be key pieces of evidence in inventorship disputes as well. Only those who contributed to the conception of the invention are inventors. Notebooks can shed light on who conceived the invention and who merely carried out the inventor's conception.

n all these situations, the patentee's ability to prove the dates of invention may determine whether it is able to obtain and protect its valuable patent rights. Laboratory notebooks are often the documents that show the earliest date of invention. Because laboratory notebooks are often key pieces of evidence, it is important that inventors and those working with them use good laboratory notebook practice.


Conception occurs when the inventor forms in his mind a definite and permanent idea of the complete and operative invention as it is to be applied in practice. The idea must be sufficiently definite and clear, so that one of only ordinary skill in the field could make and use the invention without extensive research or experimentation.

The inventor's (or inventors' ) notebook entries are obviously of prime importance in proving invention. To evidence conception, a notebook entry should show the inventor's understanding of the invention in sufficient detail to teach the invention to one of ordinary skill in the art. A notebook entry describing the problem to be solved or the goal hoped to be achieved does not prove that the inventor conceived the solution to the problem or the method of achieving the goal. For example, if the invention is a new compound, the inventor must be able to define the new compound and describe how to make it.

Some inventions are the result of accidental creation. When creation comes before conception, the date of conception is the date the inventor first appreciated what he made. For example, an inventor may not have intended to make a new compound, but may, in fact, have made something new. The inventor must have understood what he had done and appreciate or recognize the features that comprise the invention. The inventor has not conceived of the invention until he recognizes that he has made a new compound and can identify it and how to make it again. Obviously, each notebook entry should be dated, so that it can be used later to show a date of invention. In addition each and every notebook page should be signed by the person who writes in the notebook and promptly signed and dated by a witness, specifically someone other than the inventor or co-inventor.

Actual Reduction to Practice

Actual reduction to practice requires the construction of a physical embodiment of the invention that works for its intended purpose. Reduction to practice is typically more difficult to prove than conception. Inventors, and those working with them, should document all efforts to reduce the invention to practice and the results obtained and observations made along the way with attention to the nature of the invention. For example, if the invention is a new compound, then it may be sufficient to show that the compound was successful made and characterized. Test results, such as NMR spectra, showing that the new compound was actually made by a certain date, are useful in that circumstance. However, if the invention is a new method of making a known compound, then those same test results are of little usefulness in showing that the compound was made by a new method. The laboratory notebook can be used to describe each step of the method used to make the compound and the results of any tests that demonstrate that the method resulted in the desired compound. Each page should be witnessed by a non-inventor, preferably by someone who has the education and experience to understand what the inventor is disclosing in the notebook in case he or she is needed to corroborate the inventor's testimony in the future.


In an interference proceeding, the party that was first to conceive an invention but last to reduce the invention to practice has priority if he can show that he exercised reasonable diligence from a time before the other party's conception date to his own reduction to practice date. Where diligence is the issue, the question is whether there was reasonably continuing activity from the date of conception to reduce the invention to practice. Notebook pages showing tests and analysis done during the relevant time period can be used to show continuing activity toward reduction to practice. Non-inventors, as well as inventors, can be engaged in the continuing activity showing diligence. Accordingly, persons working for or with the inventor should keep a notebook in the same manner as inventor.

Best Practices

Here is a list of good laboratory notebook practices to follow:

- Use a hard-bound notebook with numbered pages.

- Number each notebook and assign one notebook to one individual at a time.

- Write in your notebook and in no one else's. Do not let others write in your notebook.

- Write in pen, not pencil.

- Write a detailed and accurate description of new ideas and all work done to develop those ideas. Include drawings, diagrams, flow charts and photographs.

- Avoid shorthand and abbreviations unless clearly understood by others in the field

- Describe discussions about new ideas including the date the discussion was held, the individuals who participated and their contribution.

- Describe all experiments and tests performed to develop the invention including the date they were performed, the reason(s) they were performed and the significance of the results obtained.

- Sign and date each page of the notebook contemporaneously with the writing in a timely manner or as close to it as practicable.

- Promptly have someone who will not be an inventor (but does understand what is described on the page) sign and date each page.

- When the notebook is full, make a copy of the entire notebook, keep the original in a safe place and start a new notebook.