A U.S. provisional patent application is one that can sometimes be quickly and cheaply filed to obtain a filing date for an invention. Under today’s “first-to-file” system, the first of two competing independent inventors (e.g both invented similar products) to file a patent application and obtain a filing date prevails over the other inventor who gets a later filing date.  Even if the other inventor invented first, the other inventor loses the priority battle if the other inventor is the second to file.

But a provisional patent application expires one year after it is filed. To keep the filing date of the provisional application, one should follow-up the provisional filing by filing, within the one year, some form of non-provisional application.  This could be a U.S. non-provisional application, a PCT international application, or an application in a foreign country. This later-filed application must claim priority to the filing date of the provisional application. 

A U.S. provisional application may, in some circumstances, be cheaper and faster to file than a U.S. non-provisional application. For example, unlike non-provisional applications, formal patent drawings are not required.  Informal drawings, including hand-drawn sketches and photographs, are permissible. 

Also, because provisional applications are not examined by examiners, patent claims, which claim that which the inventor regards as the invention, are not required (although they are still a very good idea as discussed below). And the written description can be informal. An inventor who has already written a white paper or a technical article can sometimes just file the white paper or the technical article as the provisional application.  

But, notwithstanding the above, provisional applications are still subject to some of the same requirements as non-provisional applications. It must, for example, describe the invention subject matter in sufficient detail to show that the inventor actually invented that which the inventor claims as the invention. That is, the application must “show possession” of the invention at the time of filing. The provisional application also must, just like a non-provisional application, describe to one of ordinary skill in the relevant technology (e.g one of ordinary skill in the art) how to make and use the invention.  

Because of these requirements, there are potential pitfalls with provisional applications. Patent claims force an inventor to distill in just a few words what the essence of the invention is. 

Because provisional applications do not require claims, an inventor who omits the discipline of writing claims may misfocus the application and omit describing the true points of novelty of the invention. 

Or an inventor may describe one or more points of novelty but fail to describe how to make and use the invention with those points of novelty (i.e., failure to enable the invention). If the points of novelty are not described and enabled in the application, then the provisional application may be worthless.  A patent attorney may provide intellectual property legal advice to help an inventor to identify the points of novelty and to describe and enable them.

Another potential pitfall is describing the invention too narrowly. An inventor writing their own provisional application may successfully identify and enable the points of novelty, but may describe the invention too narrowly. Inventors often initially develop a single way of implementing their idea. The patent application must not be limited to that single implementation! Once the points of novelty are identified, it may become apparent that there are multiple ways of implementing products that incorporate the points of novelty. A patent attorney may help an inventor to think more broadly about their invention and how to describe the invention without being unduly narrow.

Thus, there are trade-offs between filing a high quality attorney-drafted patent application versus an inventor-drafted provisional application. But the choices are not limited to just those two options. Attorneys can provide varying levels of assistance to an inventor. The budget and the degree of attorney involvement is something to be discussed between the inventor and the patent attorney.

There are times when a provisional application makes sense. An inventor may not know initially whether the invention truly will have economic value. Will there be a market for it? Will it be possible to mass produce it?  Can it be manufactured at a financially viable cost? Can issues with the current prototype be overcome? Can investors be located? A lower-cost provisional application gives an inventor additional time to explore the above and other issues before deciding whether to invest funds in a non-provisional application.

Another time filing a provisional application may make sense is when an inventor is still developing the invention. The inventor may not have built a prototype but still want to protect the idea. Or, the inventor may be still be coming up with improvements to the invention. 

In this situation, an inventor may file a series of provisional applications during the one year period (i.e. from the date of the first application filing), and then file a non-provisional application on what is then a marketable implementation of the invention.

An inventor’s specific situation and needs should be discussed with a patent attorney who can explain the options available and their advantages and disadvantages.