The standard of review for patent claim construction may sound like a dull procedural issue, but it is one of the most important topics in patent law today. Essentially every patent case involves a fight over the meaning of the claims—the part of a patent that defines the legal right. The Federal Circuit reviews claim construction de novo, based on the Supreme Court’s 1996 holding in Markman v. Westview that claims construction is an issue for the judge, not the jury. But the Teva petitioners argue that this is yet another case in which the Federal Circuit has made inappropriate patent-specific rules: claim construction involves questions of fact (as the Supreme Court noted in Markman), which can be reviewed only for clear error. Amicus briefs from the United States, various IP law associations, and some prominent law professors also favor more deferential review, arguing that claim construction often requires expert testimony about the meaning of terms to scientists at the time the claims were written, and that requiring these issues to be relitigated at the appellate level imposes unnecessary costs on both litigants and the judiciary.

This case might thus seem to be a slam dunk against the Federal Circuit, which has a poor record before the Supreme Court, including five unanimous reversals last Term. Yet Markman did ultimately conclude that claim construction should be treated as “purely legal,” and the Federal Circuit’s de novo approach is supported by all 20 operating companies that joined an amicus brief, including firms in high tech, medical technology, and service industries. These parties argue that patent claims should be defined uniformly and by the public record; that conflicting extrinsic evidence is merely a sign that the claim is indefinite; and that requiring discovery before claim construction and then fighting over which findings are “factual” would increase, not decrease, litigation costs. It is unclear which of these competing concerns the Supreme Court will find most convincing, but its decision will affect nearly every patent case and will thus be closely watched for by the patent community.

Read a longer argument by Prof. Lisa Ouelette at here.