## Facts

- Richard C. Price and Dale R. Symsek (with co-inventor Nancy P. Regelin) sought patent rights to a “variable temperature waste heat recovery system,” leading to a U.S. Patent and Trademark Office (PTO) interference.
- Symsek and Regelin, engineers for U.S. Steel’s American Bridge Division, filed a patent application on February 1, 1985; it later issued as U.S. Patent No. 4,628,869 (Dec. 16, 1986) and was assigned to U.S. Steel.
- On December 11, 1987, Price filed a patent application that copied claims from the ’869 patent to provoke an interference (Interference No. 102,101).
- The count involved a closed-loop waste-heat recovery system for a process heater whose exhaust-gas temperature varies over the operating cycle; the system routes heat-transfer liquid through a first heat exchanger (heated by exhaust gas), then to a reservoir, and then to a second heat exchanger to heat a recipient fluid, using the reservoir to moderate temperature swings.
- It was uncontested that Symsek conceived the invention in February 1983.
- Price attempted to prove that he conceived the invention before February 1983 and therefore should receive priority.
- To corroborate his earlier conception claim, Price relied substantially on testimony from his company’s secretary, who stated that she saw a drawing of the idea in March 1982.
- The PTO Board of Patent Appeals and Interferences found the secretary’s testimony credible, but treated it as insufficient corroboration because she did not attribute the drawing to Price and did not show an understanding of what the drawing depicted.
- The Board awarded priority to Symsek (and Regelin). Price appealed to the United States Court of Appeals for the Federal Circuit.

## Issues

1. What standard of proof governs a junior party’s attempt in a PTO interference to prove priority facts against an issued patent: clear and convincing evidence or beyond a reasonable doubt?
2. If the Board applied an overly demanding burden of proof, must the priority award be vacated and remanded for reconsideration under the correct standard?

## Decision

- The Federal Circuit held that the Board used an incorrect standard of proof by effectively requiring Price to prove priority-related facts “beyond a reasonable doubt.”
- The correct burden in this setting is clear and convincing evidence.
- Because the Board’s evaluation of Price’s evidence was tied to the wrong burden, the Federal Circuit vacated the Board’s award of priority to Symsek.
- The case was remanded to the Board for reconsideration of the evidence under the proper standard.

## Legal Principles

- PTO interference proceedings are civil proceedings; a criminal-law burden such as “beyond a reasonable doubt” is not the proper measure for proving priority-related facts.
- When an interference challenges priority against an issued patent, the party seeking to overcome the issued patent’s position must prove the necessary priority facts by clear and convincing evidence.
- An inventor’s testimony about conception and related events generally must be corroborated by independent evidence, evaluated under a rule-of-reason approach rather than rigid formal requirements.
- When an administrative tribunal applies an expressly incorrect burden of proof that affects its fact-finding on priority, the proper appellate remedy is vacatur and remand so the tribunal can reweigh the record under the correct standard.

## Conclusion

Price v. Symsek required the Federal Circuit to correct the PTO Board’s use of a near-criminal burden in an interference: the court held that priority and related proof must be shown by clear and convincing evidence, vacated the Board’s award of priority to Symsek, and sent the case back for a new evaluation under the proper evidentiary standard.


Price v. Symsek, 988 F.2d 1187, 26 U.S.P.Q.2d 1031 (1993)