SAN FRANCISCO — At last resolving an issue that's raged in patent circles for 16 years, the U.S. Supreme Court ruled Tuesday that district court claim-construction decisions in patent cases are owed more deference than they've been receiving from the U.S. Court of Appeals for the Federal Circuit.

The high court ruled that the factual findings underpinning claim construction—typically the meaning of technical phrases to persons skilled in the art at the time of the patent application—may not be discarded on appeal unless they are clearly erroneous. A district judge's ultimate conclusion as to what the claims mean is still subject to de novo review, however.

Justice Stephen Breyer's 7-2 decision in Teva Pharmaceuticals v. Sandoz is expected to lead to the introduction of more expert evidence at the district court level, particularly when litigants are confident they're on the same page as the trial judge and want to strengthen a ruling for appeal.