Guest post by Lisa Larrimore Ouellette (Visiting Fellow, Yale Law School Information Society Project) and Jonathan Masur (Deputy Dean and Professor of Law, University of Chicago Law School).

In our new draft article, Deference Mistakes, we examine indefiniteness doctrine as one example of how decisionmakers sometimes mistakenly rely on precedents in inapposite contexts. So we were very interested in the Supreme Court’s reformulation of the indefiniteness standard in Nautilus v. Biosig on Monday, and particularly in how this decision will affect the indefiniteness standard applied in the examination context.

Pre-Nautilus, claims under examination at the PTO were supposed to be evaluated under a stricter indefiniteness standard than granted claims. In Exxon Research (2001), the Federal Circuit stated that to “accord respect to the statutory presumption of patent validity,” it would find granted patent claims indefinite “only if reasonable efforts at claim construction proved futile” and the claim was “insolubly ambiguous.”

The obvious corollary to the Federal Circuit’s holding in Exxon is that when the presumption of validity does not apply, the indefiniteness standard should be more stringent. The BPAI explicitly clarified this point in the precedential Ex parte Miyazaki (2008) when it held that examiners should use “a lower threshold of ambiguity” such that claims are indefinite if “amenable to two or more plausible constructions,” and the MPEP emphasizes this point.

As we describe in Deference Mistakes, however, the less stringent “insolubly ambiguous” standard was mistakenly imported into the examination context and repeatedly cited in BPAI and PTAB decisions even after Miyazaki. And once ambiguous claims are granted, they are entitled to the presumption of validity and are less likely to be struck down, notwithstanding that they were granted under a mistaken standard.  The affirmance of these patents on appeal following infringement proceedings likely led to the PTO granting even more indefinite patents, which were then upheld on appeal, a vicious cycle. And if these patents came to be seen as the new normal, that could have made the PTO even more permissive. The result could have been creeping decay of the PTO’s effective indefiniteness standard, with indefinite patents begetting ever more indefinite patents.

At first glance, Nautilus appears to fix this problem of two different legal standards that might be mistakenly applied in the wrong context. In footnote 10, the Supreme Court states that the “presumption of validity does not alter the degree of clarity that §112, ¶2 demands from patent applicants,” suggesting that the legal test for indefiniteness should be the same in the infringement and examination contexts. The Court expressly leaves open whether this evaluation of the claims involves subsidiary factual findings and whether deference is due to any such findings—issues the Court will return to next Term in Teva v. Sandoz. But however these fact-based issues are resolved, it seems that Miyazaki‘s articulation of the legal standard for indefiniteness is no longer good law (unless, of course, the Federal Circuit adopts this as the unitary test).

Doctrinally, this requirement of a unitary legal standard for indefiniteness seems clearly right: as the Supreme Court explained in Microsoft v. i4i, the presumption of validity required by §282 is an evidentiary standard that requires invalidity to be proven by clear-and-convincing evidence, and it is thus inapplicable to questions of law. Eliminating the dual standard also has the apparent benefit of preventing the kinds of overt mistakes we point out in Deference Mistakes.

As we explain in Deference Mistakes, however, eliminating the formal legal distinctions between “deference regimes” may not solve the problem where such deference arises from functional considerations. We worry that preventing the PTO from applying “a lower threshold of ambiguity” might inadvertently undermine the PTO’s current efforts to improve patent claim clarity. Although the EFF cheered Nautilus for being likely to “invalidate many more patents,” the Court suggested at p. 12 that the test “the Federal Circuit applies in practice” may be fine, so on remand the Federal Circuit may well use the same analysis under a new name. Even if indefiniteness is a purely legal question such that the presumption of validity has no formal effect, in practice courts may apply a relatively loose standard due to an understandable reluctance to impose the drastic penalty of invalidity just because a claim could have been written more clearly. In the examination context, where applicants have the ability to amend vague claims, the PTO’s efforts to demand greater clarity make sense. But if the looser indefiniteness standard from the infringement context is incorporated into the examination context—no longer as a doctrinal mistake, but as a legal requirement—it may subvert these efforts and exacerbate the problem of ambiguous patents.