Invalidity challenges before the USPTO Patent Trial & Appeal Board (the “PTAB” or “Board”) are now routinely filed in connection with patent infringement litigation in district courts. While the Federal Rules of Evidence generally apply in both proceedings, different rules of practice before the PTAB create procedural wrinkles that practitioners should keep in mind.1 Evidentiary motions, for example, are a specific area where there are substantial differences in form, substance, and timing between the two proceedings.

In contrast with district court, where a party must move to have evidence admitted and the proponent bears the burden of establishing admissibility, an item of evidence is considered “in evidence” upon filing in a patentability proceeding before the PTAB. It is then the opponent who bears the burden of establishing inadmissibility—namely, that the material sought to be excluded is inadmissible under the Federal Rules of Evidence (the “FRE”).2

Evidentiary motions before the PTAB not only differ from the equivalent motions in district court, they also differ from other motions before the PTAB. For example, motions to exclude evidence are virtually unique in that they do not require Board authorization prior to filing.3 This renders evidentiary motions in patentability proceedings susceptible to abuse. For example, excessive creativity in drafting evidentiary motions often results in a denial of the motion.


An objection to evidence before the PTAB “must identify the grounds for the objection with sufficient particularity to allow correction in the form of supplemental evidence.”4 The rules thus give the proponent of the evidence the opportunity to correct the objected-to evidence by serving supplemental evidence within ten business days of the service of the objection.5

Contrary to the explicit mechanics outlined for objecting to evidence, the PTAB has issued little guidance for handling supplemental evidence. For example, no specific rule provides for the filing of supplemental evidence with the Board, instead only service on an opposing party is particularly addressed.6 This has led to differing outcomes when such supplemental evidence has been filed. For example, in Gnosis SPA v. South Alabama Medical Science Foundation, the Board instructed that supplemental evidence offered in response to an evidentiary objection should not be filed; rather, such evidence should be served on opponent and if opponent moves to exclude the evidence, proponent can seek authorization from the Board to file an opposition to the motion to exclude its evidence.7 In Valeo North America, Inc. v. Magna Electronics, Inc., however, the Board allowed for the filing of supplemental evidence, as opposed to simply service of the evidence on the opposing party.8

If, after receiving the supplemental evidence, an opponent still believes the evidence is inadmissible, the opponent may file a motion to exclude the evidence at the end of discovery. The rules provide that a motion to exclude evidence must “identify the objections in the record in order and must explain the objections.” Notably, “[a] motion to exclude must explain why the evidence is not admissible (e.g., relevance or hearsay) but may not be used to challenge the sufficiency of the evidence to prove a particular fact.”

In addition to strict compliance with procedure, the Board also generally seeks to preserve a complete record. Even if the motion to exclude is properly and timely made and even if a proponent’s arguments in favor of the evidence are without merit, the Board may still decide to deny exclusion.9 The Board has often found that “the better course is to have a complete record of the evidence to facilitate public access as well as appellate review.”10

As an example of the content of a motion to exclude evidence, one Board panel provided that a motion need only include the following information:

  1. Identity of the exhibit and portion thereof sought to be excluded: test data described in Exhibit 1005, Example 1.
  2. Objection: Hearsay: Fed. R. Evid. 802; 37 C.F.R. § 42.61(c).
  3. An objection was made in an Objection to Evidence, filed [state date filed]. See Ex. 2011, page x, lines y–z.
  4. Petitioner relies on the objected data on pages 5–6 of the Petition.
  5. The relied upon data is hearsay. Petitioner has not presented the testimony of any individual having any first-hand knowledge of the testing data described in Example 1.11

The PTAB has often repeated that a motion to exclude is not a vehicle for addressing the weight to be given evidence. As one panel noted, “[i]f a motion addresses only admissibility, then ‘no problem.’ But if the motion addresses weight, then ‘no dice.’” Practitioners may be challenged to avoid discussing the weight of evidence or may be tempted to dress a substantive argument as an admissibility argument. The Board will typically not entertain these motions and will likely deny. It follows that practitioners should temper the urge to draft overly creative evidentiary motions.

The Board’s general approach to motions to exclude was outlined in Corning Inc. v. DSM IP Assets B.V.12 Similar to a district court in a bench trial, “[t]he Board, sitting as a non-jury tribunal with administrative expertise,” is considered “well-positioned to determine and assign appropriate weight to evidence presented.”13 Similarly, Patent Office rules note that Administrative Law Judges (“ALJs”) require less technical and expert analysis and provide that “[t]he Board may exclude or give no weight to the evidence where a party has failed to state its relevance or to identify specific portions of the evidence that support the challenge” in the petition.14 Because ALJs are scientifically trained and knowledgeable of the technological issues over which they preside, they are less inclined to exclude evidence on evidentiary grounds and more likely to accord evidence the weight to which they believe it is entitled. The Federal Circuit has long upheld the belief that it is within the Board’s discretion to assign the appropriate weight to be accorded to evidence.15

Common Motion to Exclude Maneuvers

1. Unqualified or Unreliable Declarant

The Board has often concluded that a motion to exclude on the basis of an allegedly unqualified or unreliable expert or declarant goes to the weight of the declaration.

For example, in Flir Systems, Inc. v. Leak Surveys, Inc., the party opposing an expert declaration concerning prior art argued that “that [the expert] is not sufficiently qualified, from a technical point of view, to voice opinions on the scope and content of the prior art.”16 In denying the motion to exclude the expert’s declaration, the Board noted that “scope and content of the prior art are factual matters. . . . Petitioner’s basis for exclusion in reality goes to the weight we are asked to assign [the expert]’s testimony.”17 The opponent also pursued exclusion of the expert declaration from a different angle, arguing that an expert declaration containing conclusions “supported by only his ipse dixit18 is inherently unreliable evidence. To this, the Board “elect[ed] to take Petitioner up on evaluating and assigning ‘weight’ and decline[d] to ‘exclude’ the [expert’s] testimony even if, at the end of the day, [the Board] find[s] it is not entitled to any weight.”19 Accordingly, even if the Board were to agree that an expert’s credentials are “not the most desirable,” the Board will consider the testimony and give such weight as it deems appropriate.20

2. New Evidence and Evidence Not of Record

The Board has made clear that a motion to exclude is not the proper vehicle by which to challenge evidence on the ground that the evidence is “new” or presents new arguments. In particular, “[w]hether a reply contains arguments or evidence that are outside of a proper reply under 37 CFR § 42.23(b) is left to [the Board’s] determination.21 Similarly, “a motion to exclude is not a proper vehicle for a party to raise the issue of cross-examination exceeding the scope of the direct testimony.”22 When addressing a motion to exclude evidence on the grounds that the evidence is new or presents new arguments, the Board generally considers such arguments as addressing the sufficiency of the evidence to prove a particular fact and thus the weight of the evidence rather than its admissibility.23 In short, motions to exclude evidence on the basis that a proponent has introduced new evidence or arguments will likely fail.

3. Irrelevant Evidence

The Federal Rules of Evidence have created a balancing test that district courts and the PTAB apply to answer questions of relevance under FRE 401. For example, in Apple Inc. v. DSS Technology Management, Inc., a party sought to exclude certain exhibits for failing to be contemporaneous with the patent at issue, or for being undated, and that as such the exhibits were not relevant for the purposes for which they were proffered. In applying the balancing test, the Board concluded that the party’s arguments as to the relevance of the exhibits, in view of their late or uncertain dates, concern the weight that the Board should accord to those exhibits, rather than their admissibility.24

As to hearsay, which is also subject to a balancing test, the PTAB noted that “the law is well established that the Board will not exclude evidence that is proffered to show what a person of ordinary skill in the art would have known about the relevant field of art.”25 Thus, where the evidence is offered only for the alleged effect that the statements contained therein would have on the ordinarily skilled reader, the Board will not exclude.26

When a balancing test applies, the Board is likely to fall back on its experience in considering the evidence and decide to make the evidence part of the record. The PTAB has emphasized that “because the Board is not a lay jury, and has significant experience in evaluating expert testimony, the danger of prejudice in [the patentability] proceeding is considerably lower than in a conventional district court trial.”27 Thus, when a balancing approach is applied to evidence considerations, such as with FRE 403 relevance and FRE 703 hearsay, the Board often applies a lower threshold for admissibility compared to district court.

4. Authentication

Non-patent literature, such as newspaper articles, journal articles, advertisements, and poster presentations for example, often require a greater showing of authenticity under FRE 901(a) than patent literature. This showing, or lack thereof, can be more reliable grounds for exclusion than others mentioned herein because of its technical, formalistic nature. In one case, the Board granted a motion to exclude evidence of website printouts taken from the Wayback Machine. The Wayback Machine returns images of webpages corresponding to web addresses captured on a given date. It is a potential wellspring of non-patent literature prior art. The Board in Neste Oil, however, adhered strictly to FRE 901(a) requiring that “the proponent must produce evidence sufficient to support a finding that the item is what the proponent claims it is.” The Board concluded “[w]hen offering a printout of a webpage into evidence to prove a website’s contents, the proponent of the evidence must authenticate the information from the website itself, not merely the printout.”28 As authentication issues are more procedural than substantive, opponents may be more successful in moving to exclude evidence on authenticity grounds than other grounds.

5. Translations

Evidence in the form of materials written or otherwise provided in a foreign language are ripe for challenge before the PTAB. When foreign language evidence is presented, the Board often loses its ability to assess and give weight to the substance of such evidence absent a translation and document attesting to accuracy of the translation. In light of this, the Board has granted motions to exclude such evidence as failing to comply with 37 C.F.R. § 42.63(b).29


Regardless of which party moves to exclude evidence before the PTAB and which grounds are advanced to support the motion, the motion should not be used to challenge the sufficiency of the evidence to prove a particular fact. Some discussion of the weight of the evidence sought may be necessary, but the Board has indicated that any extended discussion about the weight of the evidence (rather than its admissibility) is inappropriate. Where opponents bulk up arguments in the hopes of persuading the Board to grant exclusion, they can unintentionally persuade the Board that the issue is a factual and substantive one, and not an admissibility issue.30 Beyond conflating admissibility and sufficiency, the fact that different rules for excluding evidence and different considerations of practice before scientifically-trained ALJs apply at the PTAB requires that proper consideration of the mechanics and maneuvers of motion practice at the PTAB be given in order increase the odds of filing a successful motion or opposition.