Statutory Rules

Rules governing novelty depend on whether the filing date is before March 16, 2013 (pre-AIA), or on or after March 16, 2013 (AIA).

Meanings of Terms

For an invention to be on sale, two elements must be met: (1) an embodiment of the invention must be the subject of a commercial offer for sale; and (2) the invention must be ready for patenting.  The second element must be established by showing either that the inventor had reduced the invention to practice or that the inventor prepared documents that enable a PHOSITA to make and use the invention.

Novelty Under AIA

Under AIA law, a claim is not novel if prior to the filing date: the public uses the invention; a printed publication describes the invention; the invention is on sale; or the invention is otherwise available to the public.  However, the inventor may make public disclosures of the invention up to one year prior to filing for a patent without defeating the novelty of her own invention.

Under pre-AIA law, a claim is not novel if prior to the invention date: the public knew of or used the invention in the United States; a printed publication described the invention; or the invention was described in an issued patent or a patent application published by the PTO.

Novelty Under Pre-AIA

Under pre-AIA law, the statutory bars make a claim invalid if prior to the critical date (i.e., prior to one year prior to the filing date): the invention was patented anywhere in the world; the invention was described in a printed publication anywhere in the world; the invention was in public use in the United States; or the invention was on sale in the United States.

Statutory Bars
On Sale

A reference is considered a printed publication based on its public accessibility.  Even temporary displays of a reference may constitute a printed publication depending on the circumstances (e.g., duration; audience expertise; likelihood of copying).

Printed Publication

A claim that is not novel is said to be anticipated by the prior art.  Prior art consists of evidence that the invention is not new to the public.  One such piece of evidence in the prior art may be a document—called a reference—that describes every element in a patent claim, either expressly or inherently. 


Anticipation of a patent claim can occur only where the prior art anticipates the claim prior to a certain date—called the priority date—and that date will be either the invention date or the filing date, depending on whether the pre-AIA or AIA set of rules governs.

Public Use

An invention is known or used if the public is not restricted from gaining access to knowledge or use of the invention.  This does not require that a significant portion of the public know of or use the invention.  Actual access by the public also is not necessary.  Transferring an embodiment of the invention to another person is a public use if the transfer is made without any limitation or restriction. 

A use of the invention that is restricted for testing and experimentation purposes, even if open to public view, is not a "public use."  Courts consider evidence suggesting whether an inventor retains control of the invention when she allows others to use it.

Experimental Use Exception
Pre-AIA or AIA?

Priority disputes arise where two inventors claim a patent on the same invention.  Resolving these disputes depends on whether the pre-AIA or AIA set of rules govern.  If the inventor filed for a patent prior to March 16, 2013, pre-AIA rules govern.  If the inventor filed for a patent on or after March 16, 2013, AIA rules govern.

Priority (Pre-AIA) - First to Invent

Under pre-AIA rules, the first to invent is given priority.  The first to reduce to practice (RTP) will be deemed the first to invent, unless the second to RTP can show that he was the first to conceive and that he worked with reasonable diligence (from just before the other inventor’s conception date through his own RTP).

Priority (AIA) - First to File

Under AIA rules, the first inventor to file for a patent is awarded priority. Nevertheless, exceptional circumstances could exist that would result in the patent going to the second to file. 


Such circumstances include: the first-to-file inventor insufficiently disclosed the invention in the application; the second-to-file inventor made a prior disclosure (not more than one year prior to the second-to-file inventor's filing date); the first-to-file inventor derived his invention from the second-to-file inventor; and the first-to-file inventor abandoned his application prior to its publication.

Reduction to Practice (RTP)

Reduction to practice (RTP) occurs when the inventor has completed a working model (or in other words, an embodiment) of the invention.  To be an RTP embodiment, the embodiment must provide the inventor with confidence that the invention does work.  Reduction to practice does not include experimental models.


Reduction to practice may be actual or constructive.  Actual RTP occurs where the inventor creates an actual embodiment of the invention.  Constructive RTP occurs where the inventor files a patent application that satisfies the requirements of written description, enablement, and best mode.

Practice Problems

Question 1

Paul and Quincy both invent the same invention. Paul conceives of the invention on January 1, 2010. Quincy conceives the same invention on February 1, 2010. Paul reduces to practice on March 1, 2010. Quincy reduces to practice on April 1, 2010. Quincy files for a patent on May 1, 2010. Paul files on June 1, 2010.

Question: Who is awarded priority?

Question 2

Alice and Betty both invent the same invention. Alice conceives of the invention on January 1, 2010. Alice does nothing to RTP the invention until July 1, 2010, at which time she starts working toward filing an application with the PTO, using reasonable diligence all the way to her filing date of September 1, 2010. Alice never does create an embodiment of the invention. Betty conceives the same invention on July 4, 2010, and reduces to practice by August 1, 2010. Betty files for a patent on October 1, 2010.

Question: Who has priority as between Alice and Betty?

Question 3

Mark conceives an invention that no one else has thought of. Two years after Mark conceives of the invention, he writes it down in great detail as part of his PhD dissertation. When Mark submits that dissertation to the university, the university catalogues and indexes it in its library. Ten months after submitting his dissertation to the university, Mark applies for a patent on his invention. His filing date is February 10, 2016.

Question: Does Mark’s application for a patent meet the requirement for novelty?

Question 4

Linda has created a solar-powered automobile (that stores electricity for cloudy days). She wants to show her friend, Tom, her invention, who is an avid environmentalist. Before she does, though, Linda makes Tom promise that he won’t tell anyone about her new invention. After Tom promises, Linda shows it to him and lets him take a short drive around the block for the purpose of testing how the car drives by someone other than herself. Tom absolutely loves it. There on the spot, Tom offers to buy it from Linda for a million dollars. Linda refuses, telling Tom that it’s not for sale. Two years later, Linda files for a patent on March 10, 2013.

Question: Do any of the facts herein invalidate Linda’s patent claim?

Question 5

Ringo and George invent the same invention. Ringo conceives of the invention on December 1, 2012. He reduces to practice December 24, 2012. George independently conceives the invention January 1, 2013 and reduces to practice two days later. George files for a patent on March 20, 2013. Ringo files for a patent on March 21, 2013. Both Ringo and George have been reasonably diligent in their efforts to reduce to practice and file for a patent. Neither have published anything about their work.

Question: Who has priority to the invention as between Ringo and George?

Answer to Question 1

Paul. Pre-AIA rules govern because the filing occurred prior to March 16, 2013. First to invent is given priority. Paul is the first to RTP so he is the first to invent. Also, Quincy did not conceive prior to Paul.


Answer to Question 2

Alice. Pre-AIA rules govern because the filing occurred prior to March 16, 2013. Betty was the first to RTP. However, Alice was the first to conceive, and she was reasonably diligent prior to Betty’s conception all the way to her own filing date (and filing counts as constructive RTP).

Answer to Question 3

Yes.  AIA law governs because Mark’s filing date is after March 16, 2013. Mark may make a public disclosure of his invention during the year prior to his filing. Mark’s dissertation is an enabling reference. So when Mark submitted his dissertation to the university, and the university catalogued and indexed it, he made a public disclosure of an enabling reference in the form of a printed publication. That occurred within one year prior to his filing date. That disclosure did not defeat his claim of novelty.

Answer to Question 4

No.  Pre-AIA law governs because Linda’s filing date is prior to March 16, 2013. The relevant question, then, is whether Linda’s claim is invalid under the statutory bars. Does either the public-use or the on-sale bar apply? If either a public use or an offer for sale occurred in the stated facts, that act would have occurred more than one year prior to her filing date, so the statutory bar would invalidate her claim. But neither apply here. With respect to the public-use bar, Tom’s driving of the car is not a public use. Linda controlled Tom’s use, restricting it to driving it around the block. Moreover, Tom’s driving was likely an experimental use given that Linda let him drive it to test its performance by someone other than herself.


With respect to the on-sale bar, Linda never sold nor offered to sell the car. Tom’s offer to buy does not constitute an offer to sell.  Hence, none of the facts bar Linda from obtaining a patent on her invention.

Answer to Question 5

George. AIA law governs because filing occurred after March 16, 2013. Under AIA rules, the first to file has priority. George was the first to file. Conception and RTP dates are irrelevant.