Some practitioners file provisional patent applications that are skimpy in order to get a filing date for a client. I have often wondered if this borders on malpractice.
In an example where a skimpy provisional application is filed and a full non-provisional application is filed a year later, there are two filing dates: one for the skimpy material and one for the rest of the information, which is a year later. If the provisional is filed in order to beat a statutory bar date (e.g., one year from public use or disclosure in the US or before divulgation in Europe), the information in the subsequent non-provisional application would be outside the bar date and could thereby invalidate the patent.
In addition to bar date problems, the differences between the provisional and non-provisional leave the door open for a competitor to file a patent or otherwise cause the applicant problems down the road.
The provisional must have all the elements of the non-provisional, including adequate written description, for it to serve as an adequate filing date. An adequate written description is generally what is lacking in a skimpy provisional application.
I think there should be some compelling business need for a skimpy provisional. For example, I have used provisionals where the inventor is flying off the next day to present a paper at a conference. There is a business need where Patent Pending is desired but not necessarily an issued patent, such as where the inventor wants to scare off competitors or use Patent Pending in some promotional activity.
The big danger of using skimpy provisionals is that the client is potentially voiding any issued patent, clouding the history of the patent when time for enforcement comes around, or not fully closing the door to their competitors. Clients who are not experienced in IP law may assume that their skimpy provisional patent application is as good as any other well written patent application, and may be very disappointed when they have built their business around the application only to find out that the validity may be questionable.
Unless I feel that the client fully understands the risks of a skimpy provisional application, I won’t file them. I prefer to write provisionals just like non-provisionals, except that I don’t file the claims in the provisional. A year later, we look over the invention, review the (unsubmitted) claims, the client’s business plan, and the business market to determine if any additions need to be made, then I file the non-provisional. In this way, we capture and protect the invention as best as possible, while avoiding client wrath if they ever have to litigate the patent.