Since forever, on sale meant any offer or actual sale, regardless of who knew about it. Some have argued that the addition of "or otherwise available to the public" means that only offers that are publicly accessible count as prior art. I think this is wrong, and signed on to an amicus brief saying so. We'll see what the Court says. Note that non-public does not mean "secret." True secret activity is often considered non-prior art, but the courts have defined "public" to mean "not-secret." The question is whether that should change to be "publicly accessible."
But how big a deal is this case? How many offers for sale would be affected? Steve Yelderman (Notre Dame, and soon to be Gorsuch clerk) wanted to know as well, so he did the hard work of finding out. In a draft paper on SSRN that he blogged about at Patently-O, he looked at all invalidity decisions to see exactly where the prior art was coming from. Here is the abstract for Prior Art in the District Court:
This article is an empirical study of the evidence district courts rely upon when invalidating patents. To construct our dataset, we collected every district court ruling, verdict form, and opinion (whether reported or unreported) invalidating a patent claim over a six-and-a-half-year period. We then coded individual invalidation events based on the prior art supporting the court’s analysis. In the end, we observed 3,320 invalidation events based on 817 distinct prior art references.
The nature of the prior art relied upon to invalidate patents informs the value of district court litigation as an error correction tool. The public interest in revoking erroneous patent grants depends significantly on the reason those grants were undeserved. Distinguishing between revocations that incentivize future inventors and those that do not requires understanding the reason individual patents are invalidated. While prior studies have explored patent invalidity in general, no study has reported data at the level of detail necessary to address these questions.
The conclusions here are mixed. On one hand, invalidations for lack of novelty bear many indicia of publicly beneficial error correction. Anticipation based on obscure prior art appears to be quite rare. When it comes to obviousness, however, a significant number of invalidations rely on prior art that would have been difficult or impossible to find at the time of invention. This complicates — though does not necessarily refute — the traditional view that obviousness challenges ought to be proactively encouraged.So, let's get right to the point. The data seem to show that "activity" type prior art (that is sale or use) is much more prevalent in anticipation than in obviousness. This is not surprising, given that this category is often the patentee's own activities.
With respect to non-public sales, they estimate that a maximum of 14% of anticipation and 2% of obviousness invalidations based on activity were based on plausibly non-public sales. This translates to about 8% of all anticipation invalidations and 1% of all obviousness invalidations. Because there are about as many obviousness cases as anticipation cases, this averages to 4.25% of all invalidations. They note that with a different rule, some of these might have been converted to "public" sales upon more attention paid to providing such evidence.
A related question is whether the inventor's actions can invalidate, or whether the AIA overruled Metallizing Engineering, which held that an inventor's secret use can invalidate, even if a third-party's secret use does not. The study found that the plaintiff's actions were relevant in 27% of anticipation invalidations and 13% of obviousness invalidations. Furthermore, they found that most of the secret activity was associated with either the plaintiff or defendant--this makes sense, as they have access to such secret information.
So, what's the takeaway from this? I suppose where you stand depends on where you sit. I think that wiping out 4% of the invalidations, especially when they are based on the actions of one of the two parties, is not a good thing. It's bad to allow the patentee to non-publicly sell and have the patent, and it's bad to hold the defendant liable even if it has been selling the patent in a non-public (though non-secret) way. We're talking about 20 claims per year that go the other way - too high for my taste, especially when it means we have to start defining new ways to determine whether something is truly public.
Furthermore, the stakes of reversing Metallizing are much higher. I freely admit that the "plaintiff's secret actions only" rule has a tenuous basis in the text of the statute, but it has been the law for a long time without being expressly overruled by two subsequent revisions. Given that more than 25% of the invalidations were based on the plaintiffs actions, I think it would be difficult to reverse course.