Flip a coin for patent infringement outcome? That is what a lot of people—including federal district court judges—have thought, given that claim construction is solely a matter of law for judges to decide under the Cybor rule (taken from the 1998 Cybor Corp. v. FAS Technologies case).

Claim construction pretty much determines the outcome of most patent litigation. So the ability to review (appeal) the outcome can be key. But because claim construction is solely reviewed as a matter of law, meaning that the Federal Circuit Court of Appeals reviews the case de novo (giving it a fresh look as though it had not been heard before), the appellate court can freely substitute its opinion of the claim construction for that of the trial court. Trial courts hear fact witnesses and expert witnesses and review evidence. Appellate courts only get to read transcripts and briefs. Deference is given to the original fact-finder when reviewing facts. But if the review hinges solely on a matter of law, there is no deference. Wholesale substitution of a trial court’s decision on claim construction, which happens rather frequently, amounts to an expensive coin flip. And there has been quite a bit of controversy about this.

Now we have had a full-panel review by the Federal Circuit Court of Appeals in the Lighting Ballast Control LLC v. Philips Electronics North America Corp. case that determined that the Cybor rule remains as a matter of stare decisis (policy of courts to stand by precedent and not to disturb a settled point). Despite many briefs filed by friends of the court in the Lighting Ballast case, the coin-flip sentiment will remain.

But don’t expect this to be the last word on the topic. The Supreme Court has taken seven IP cases on review this 2013-2104 term. I strongly suspect that this case will be too tempting not to review and weigh in on. In the foreseeable future, expect to hear more about what part of claim construction is law and what is fact.