Reduction to practice is the actual physical construction of an item or the carrying out of the steps of a process for a patent. In other words, it's the form of an invention being patented that can actually be shown to someone else doing what it is supposed to do. This concept encompasses actual operation, demonstration, and testing for the intended use.

Reduction to practice is a very important element in establishing oneself as the original or prior inventor. If you file a regular patent application in which the invention is completely disclosed, it counts as "constructive" reduction to practice.

Establishing Patent Priority

The American legal system treats patent priority contests (interference proceedings) in a way that differs from most other countries. In the United States, patent registration rights belong to the inventor at the moment that they reduce their invention to practice.

The key difference is that the inventor simply needs to conceive of the idea (established by Hybridtech vs. Monoclonal Antibodies, Inc. as "a definite and permanent idea of the complete and operative invention") and then tangibly reduce it to practice to have rights. In other countries, the first person to actually file usually owns the rights.

The concept of reduction to practice prevents an inventor from having their prior invention stolen by an earlier filer. The interference proceeding is the legal procedure by which to establish ownership.

Actual Reduction to Practice

An actual reduction to practice consists of a working prototype of the invention. The prototype has to demonstrate that the invention will actually do what is claimed. In the case of a process, the process has to actually be carried out successfully.

Actual reduction to practice carries the stipulation that there must be a "practical use" for the invention if the utility of it is not self-evident.

Certain categories of patent carry additional special rules that govern actual reduction to practice. For example, designs must be an actual structure (not just a blueprint), and plants must be asexually reproduced.

An inventor can potentially claim the date of conception as the date of invention if they have been documenting their progress appropriately. The date of actual reduction to practice is the most important factor in beating an earlier patent's filing date, but properly establishing the date of conception can defeat an argument that the invention is based on prior art.

Testing Requirements for Actual Reduction to Practice

As mentioned earlier, if the practical utility of an invention is not self-evident, testing and demonstration of it are required.

A good rule of thumb is that the simpler and less theoretical the invention is, the less of a need there will be to show utility. For example, brand new technologies will require a high level of proof of utility, while improvements on existing technology usually require little to no demonstration.

The main test is whether a person "skilled in the art" agrees that the invention will do what it is supposed to. If such a person doesn't have full confidence the invention will work as advertised, then testing is required to address reasonable doubts.

Establishing Actual Reduction to Practice During an Interference Proceeding

Under MPEP 2138.05, a two-part test is used to establish actual reduction to practice: "the party constructed an embodiment or performed a process that met every element of the interference count" and "the embodiment or process operated for its intended purpose."

Other important factors to consider in establishing actual reduction to practice include:

  • The invention doesn't have to be in a commercially viable state; it just has to operate well enough to display utility (Scott v. Finney).
  • Events that occur after an actual reduction to practice can retroactively call the legitimacy of it into question (DSL Dynamic Sciences, Ltd. v. Union Switch & Signal, Inc.).
  • Evidence of a constructive reduction to practice is not necessarily sufficient to demonstrate actual reduction to practice (Wetmore v. Quick).
  • An actual reduction to practice of a production method requires a viable final product, not just a demonstration that the method can be completed (Birmingham v. Randall).
  • If a device is simple and straightforward enough, successful construction alone may serve as an actual reduction to practice (King Instrument Corp. v. Otari Corp.).
  • Testing under lab conditions must either duplicate every condition of actual use or demonstrate a relationship between the subject matter, test condition and intended functional setting of the invention (Gellert v. Wanberg).

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