Lexicon Medical v. Northgate Technologies and Smith & Nephews (Fed. Cir. 2011)
Judge Rader begins his claim construction decision with an interesting conclusion:
Because the record amply supports the trial court's interpretation of this claim term … this court affirms.
Of course the Federal Circuit's en banc decision in Cybor requires that claims be reviewed de novo and without deference to the lower court decision. Thus ,the proper question on appeal is not whether the evidence supports the lower court's decision but instead whether the lower court made the correct determination. In its actual analysis of the claim construction, the appellate panel here appears to have actually performed a complete de novo review and concluded that, indeed, the trial court's conclusions were correct. The seeming slip in the opening statement of the opinion is understandable – district court opinions on claim construction should be given some deference.
Part of the trouble with claim construction is that the analysis is rarely a binary decision for the court. Rather, there are often a large number of potential interpretations for any particular claim phrase and, courts typically construe (or refuse to construe) multiple claim phrases. Thus, the idea that a random claim construction should be correct 50% of the time is completely wrong. We also know that well informed, reasonable decision makers often disagree on the particular "best" construction of a particular claim phrase. In a recent article, Peter Menell wrote "If nothing else, the past two decades revealed the inherent difficulties of using language to define the boundaries of abstract and intangible rights." Menell, Powers, & Carlson, Patent Claim Construction: A Modern Synthesis and Structured Framework, 25 Berkeley Tech. Law Journal 711 (2011).
District courts do make mistakes in construing claims, and those should be corrected on appeal. However, apart from clear district court errors, there is no evidence that the Federal Circuit judges do a better job of construing claims than do district court judges. Offering some deference to district court decisions would give a modicum of finality to those decisions and would give some credence to the reality that claim construction involves substantial factual analysis. In his article, Menell writes that "the Federal Circuit is likely to formally rule that there is a role for district court fact-finding in the claim construction process." We will be waiting to see if Menell's prediction comes true.