A hearing before the judge to determine the meaning of words in the patent claims. (The hearing is named for Markman v. Westview Instruments. This determination is known as “claim construction.” Claim construction is critical to defining the scope of a patent so that validity and infringement can be determined. Claim construction is reviewed by the Federal Circuit de novo (that is, without deference to the district court). As a result, district court claim construction decisions are reversed by the Federal Circuit 30-40% of the time.