Who Can Testify? The POSITA Standard After Kyocera and Osseo Imaging

The Federal Circuit has now resolved a recurring objection to patent expert qualifications. An expert may testify from the perspective of a person of ordinary skill in the art even if the expert did not hold that level of skill at the time of the invention. The court's holding in Osseo Imaging, LLC v. Planmeca USA, Inc. (Fed. Cir. 2024), which followed and clarified Kyocera Senco Industrial Tools Inc. v. International Trade Commission (Fed. Cir. 2022), confirmed that the POSITA inquiry is about present competence, not contemporaneous credentials.

For retention, the doctrinal shift narrows the categorical objections available to opposing counsel and broadens the field of qualified candidates for older patents.

The law before Osseo Imaging

The pre-Osseo question was whether an expert who entered the field after the priority date could opine as a POSITA at all. The objection was familiar. If the patent's relevant date is 1999, and the expert took the field's foundational coursework in 2008, opposing counsel would argue that the witness could not speak as a person of ordinary skill at the relevant time, because the witness was not ordinary, was not skilled, and was not in the art when the time-of-invention question was being asked.

Some district courts had credited that objection at the qualification stage, treating contemporaneous practice as a threshold requirement. Others had treated it as a question of weight. The split was real enough that retention pitches for older patents routinely emphasized "in the art at the time" credentials, sometimes at the expense of the strongest available witness.

Kyocera Senco Industrial Tools Inc. v. International Trade Commission, decided by the Federal Circuit in 2022, had already pointed the doctrine in a particular direction. Kyocera held that an expert must possess the qualifications of a person of ordinary skill in the art to opine on infringement or invalidity from that perspective. The case held the expert in that matter was unqualified, but the operative reasoning was about the substantive level of skill, not the timing of when it was acquired.

What Osseo Imaging changed

Osseo Imaging confronted the timing question directly. The Federal Circuit held that an expert need not have acquired the requisite skill level prior to the time of the invention. Retroactive expertise is acceptable. What matters is that, at the time of the testimony, the expert has the qualifications of a POSITA and can opine from that perspective on the relevant questions.

The court's reasoning is straightforward. The POSITA is a legal construct used to assess what the invention would have meant to a hypothetical practitioner. The expert's job is to recreate that perspective for the factfinder. Whether the expert acquired the skill set in 1998 or in 2018 does not bear on whether the expert can describe what a 1998 practitioner would have understood, so long as the expert has the substantive technical competence to do so.

The decision does not displace the substantive-competence requirement Kyocera articulated. An expert without the requisite skill level is unqualified, full stop. The change is that "requisite skill level" is measured at the time of testimony, not at the time of invention.

What Osseo Imaging did not change

Three things did not change.

First, the expert still must articulate the POSITA's level of skill at the relevant time, and the analysis still must proceed from that perspective. Osseo Imaging is permission to testify, not permission to skip the framing.

Second, the expert's training and experience still must be sufficient to support the testimony. A general practitioner is not a POSITA in a specialized subfield merely because the practitioner acquired some exposure later. The substantive fit between the expert's expertise and the technology at issue is what Kyocera holds, and Osseo Imaging does not loosen it.

Third, the cross-examination record is still in play. Opposing counsel can still develop on cross that the expert's knowledge of the relevant time period is reconstructed rather than lived. That goes to weight, and after Osseo Imaging, it goes to weight rather than to admissibility, but the deposition transcript on the question is still part of the trial record.

Implications for retention

Three operational implications follow.

First, the strongest available technical witness for an older patent is no longer presumptively disqualified by virtue of when the witness entered the field. The diligence question is the witness's substantive competence and the witness's ability to articulate the POSITA perspective, not the witness's CV chronology.

Second, retention pitches that lean on "in the field at the time" as a primary differentiator are pitching to a standard the Federal Circuit has now declined to adopt. The differentiator is the depth of the technical expertise and the quality of the POSITA framing in the report, not the calendar.

Third, opposing counsel can be expected to redirect the objection from admissibility to weight. The cross-examination on retroactive expertise is now the relevant exposure, and it should be war-gamed in the report drafting. The declaration should anticipate the question and answer it on the face of the document, by articulating the POSITA perspective with citations to contemporaneous literature and by explaining how the expert's later-acquired expertise allows the expert to read that literature.