Revisiting Hindsight Bias: Mintz v. Dietz & Watson

In Mintz v. Dietz & Watson, an opinion penned by Chief Judge Rader, a three judge panel that also included Circuit Judges Newman and Dyk strongly admonished against the use of impermissible hindsight towards a finding of obviousness.

Despite finding that the accused products did not infringe and following a comprehensive analysis of hindsight, the CAFC further held that U.S. Patent No. 5,413,148 (the “’148 Patent”) was not invalid under § 103.

The ’148 Patent discloses a casing structure for meat products that produces the desirable checkerboard pattern on the meat’s surface by permitting the meat to bulge between the netting strands. Prior art solutions created the checkerboard pattern; however, solving an associated issue caused by the adherence of the strands during removal required an addition labor intensive and expensive step. The ’148 Patent solves the problem through an interlocking solution using a stretchable stockinette while also avoiding the more complex and costly process associated with prior art.

The ’148 Patent covers Mintz’s Jif-Pak products. Package Concepts & Materials, Inc., (“PCM”) filed a declaratory judgment action against Mintz, who in turn sued PCM for infringement alleging that PCM’s knitted meat encasement products infringe the ’148 Patent. In ruling on cross-motions for summary judgment, the District Court granted PCM’s and denied Mintz’s motions on validity and infringement.

The district correctly found all limitations in the prior art except the disputed limitation, that “each longitudinal and lateral strand of the netting arrangement intersect in locking engagement with one another.” The Court further determined that it would have been obvious to a person skilled in the art to include the “intersecting in locking engagement” claim limitation. Under a common sense analysis, the lower court reasoned that providing such a locking engagement for the intersection of each lateral and longitudinal strand would have been obvious to try when a checkerboard pattern on a meat product is desired.

On appeal of invalidity, the Federal Circuit reversed finding the District Court overreached and made a clear error to hold that it would have been “obvious to try” a locking engagement under a common sense approach. Slip Op. at 8. Common sense is nothing more than the knowledge and skill set of an ordinary meat encasement artisan. Id. at 8-9. The District Court used knitting references as analogous art to that of the claimed invention. Id. at 8. But the Court discounted that the relevant art was meat encasement. Id. Absent a record showing the pivotal knowledge resided within one of skill in the relevant art, the Federal Circuit held the lower court’s view was prohibited reliance on hindsight.

In overruling the obvious determination, the Federal Circuit found that the District Court also erred by using the invention to define the problem that the invention solves. The District Court had ruled that in solving the problem of forming a checker-board pattern, it would have been obvious to try the claimed solution, i.e., “fix each point of intersection.” Id. at 9. Chief Judge Rader construed this framing of the problem using the patented solution as another forbidden use of hindsight. Id.

Redefining the problem, the Federal Circuit held that PCM must prove by clear and convincing evidence that a person of ordinary skill in the art of meat encasement at the time of the invention would have recognized the problem and found it obvious to produce the meat encasement structure disclosed in the ’148 Patent to solve that problem. Id.

Finally, the Federal Circuit chided the lower court for failing to give substantive consideration to the objective indicia of non-obviousness. Id. at 10-11. Mintz presented considerable evidence of non-obviousness, including unexpected results, expert skepticism, copying, commercial success, praise by others, failure by others, and long-felt need. Id. at 11-12. The Federal Circuit characterized the objective indicia of non-obviousness as a powerful tool for avoiding subconscious reliance on hindsight and deemed its consideration as mandatory. Id. at 10.

The lower court had held PCM’s products do not infringe the ’148 Patent because they do not contain the claimed limitation requiring “longitudinal and lateral strands of said netting arrangement each intersecting in locking engagement with one another to form a grid-like pattern comprising a plurality of four-sided shapes.” Id. at 15. The CAFC upheld this part of the order of non-infringement because the PTO granted the ‘148 Patent based on the claim limitation that each longitudinal and lateral strand intersect in locking engagement.

Ultimately, the Federal Circuit could have simply upheld non-infringement. Yet, Mintz afforded the Court the opportunity to circumscribe hindsight in an “obvious to try” analysis.