Affirmed by published opinion. Judge WILKINS wrote the opinion, in which Judge DIANA GRIBBON MOTZ and Senior Judge HAMILTON joined.
OPINION
Southern States Rack and Fixture, Incorporated (Southern States) appeals a judgment of the district court entered in favor of Sherwin-Williams Company (Sherwin-Williams) following a jury trial. Southern States argues that the district court abused its discretion by excluding testimony from one of Southern States’ еxpert witnesses concerning a new opinion that the expert formed during trial. Finding no error, we affirm.
I.
Southern States brought this action against Sherwin-Williams, claiming that paint Southern States purchased from Sherwin-Williams was defective because it rubbed off of metal racks that Southern States manufactured. In May 2000, Sher-win-Williams responded to a discovery request by Southern Stаtes that sought the formula of the paint at issue. Sherwin-Williams indicated that it would produce the formula only if Southern States would sign a confidentiality agreement.
*594 After lengthy negotiations, Southern States and Sherwin-Williams signed a confidentiality agreement in July 2001, and Sherwin-Williams promptly disclosed a document purporting to contain the paint formula. Several days later at a pretrial conference, Southern States asserted that the document Sherwin-Williams had produced did not contain the actual formula of the paint. Though Sherwin-Williams maintained that the formula it had provided was correct, it promised to confirm this fact. On August 3, 2001, Sherwin-Williams sent a letter to Southern States providing the specific chemical composition of each ingredient identified in the earlier document.
Southern States forwarded this information to its expert chemist, Geoffrey Byrnes, who had previously issued a report and been deposed. Based on the new information, Byrnes issued a supplemental report on August 6, 2001.
Trial began on Monday, August 13, 2001. Two days later, Byrnes was called to testify. When Southern States оffered him as an expert, Sherwin-Williams conducted voir dire regarding Byrnes’ opinions. During this voir dire, Byrnes and Southern States’ counsel disclosed — for the first time — that two days earlier, Byrnes had formed a new, third opinion, and had communicated that opinion to Southern States’ counsel. 1 Specifically, Byrnes stated that he now believed that certain components of the paint were incompatible, causing it to rub off. Other than a passing reference to “the nature of the paint” during his deposition, J.A. 972, Byrnes had not previously expressed any opinion that the failure of the paint was caused by incompatible ingredients. Though Byrnes’ earlier opinions were based on the composition and physical properties of the paint, those opinions apparently focused on the behavior of the paint when applied in a particular manner, not the compatibility of its ingredients.
Byrnes also stated that his new opinion was based in part on tests he conducted in response to deposition testimony by one of Sherwin-Williams’ experts, Dr. Bernard Appleman. Though Appleman had been deposed in March 2001, Byrnes claimed that he had not received a copy of the deposition and exhibits until approximately two weeks before his trial testimony. Still, Byrnes acknowledged that he “didn’t get around to reading” these materials thoroughly until the weekend before trial. Id. at 724. In addition, counsel for Southern States asserted that counsel’s failure to disclose Byrnes’ new opinion when he learned of it two days earlier was due to “the heat of a trial.” Id. at 739-40.
On Sherwin-Williams’ motion, the district court excluded Byrnes’ third opinion due to Southern States’ failure to timely disclose it. The court allowed Byrnes to testify regarding opinions he had expressed during his deposition and in his August 6 supplemental report. Aftеr the *595 close of evidence, the jury returned a verdict for Sherwin-Williams.
Southern States then moved for a new trial, arguing that the district court erred in excluding Byrnes’ third opinion, and alternatively, that this opinion constituted newly discovered evidence. The district court held that Byrnes’ third opinion was properly excluded under Fed.R.Civ.P. 37(c)(1), which provides for the exclusion of evidence that is not disclosed in accordance with Fed.R.Civ.P. 26, including supplemental disclosures relating to experts. Applying a five-factor test discussed in
Rambus, Inc. v. Infineon Technologies AG,
II.
We review the imposition of discovery sanctions for abuse of discretion.
See Nelson-Salabes, Inc. v. Morningside Dev., LLC,
A.
1.
In relevant part, Rule 37(c)(1) provides that “[a] party that without substantial justification fails to disclose information required by Rule 26(a) or 26(e)(1), or to amend a prior response to discovery as required by Rule 26(e)(2), is not, unless such failure is harmless, permitted to use as evidence at a trial ... any witness or information not so disclosed.”
2
Of importance here, Rule 26(e)(1) requires a party
*596
to supplement its experts’ reports and deposition testimony when the party learns of new information. If the party fails to do so, the court may exclude any new opinion offered by the expert.
See Tenbarge v. Ames Taping Tool Sys., Inc.,
The lаnguage of Rule 37(c)(1) provides two exceptions to the general rule excluding evidence that a party seeks to offer but has failed to properly disclose: (1) when the failure to disclose is “substantially] justified],” and (2) when the nondisclosure is “harmless.” Here, in concluding that Byrnes’ undisclosed third opinion should be excluded, the district court applied the following fivе-factor test for determining whether nondisclosure of evidence is substantially justified or harmless: “ ‘(1) the surprise to the party against whom the witness was to have testified; (2) the ability of the party to cure that surprise; (3) the extent to which allowing the testimony would disrupt the trial; (4) the explanation for the party’s failure to name the witness before trial; and (5) the importance of the testimony.’”
Rambus,
Southern States argues that the district court erred by excluding Byrnes’ third opinion in the absence of any finding that Southern States acted in bad faith. 4 We find Southern States’ argument unavailing. Rule 37(c)(1) does not require a finding of bad faith or callous disregard of the discovery rules. While Rule 37(c)(1) requires the nondisclosure tо be “without substantial justification” and harmful, neither of these requirements suggests that the nondisclosing party must act in bad faith or otherwise culpably.
In addition, excluding evidence only when the nondisclosing party acted in bad faith would undermine the basic purpose of Rule 37(c)(1): preventing surprise and prejudice to the opposing party,
see Thibeault v. Square D Co.,
Further, we believe that the five factors articulated in Rambus are helpful in determining whether a party’s nondisclosure of evidence was substantially justi *597 fied or harmless. Four of these factors— surprise to the opposing party, ability to cure that surprise, disruption of the trial, and importance of the evidence — relate mainly to the harmlessness exception, while the remaining factor — explanation for the nondisclosure — relates primarily to the substantial justification exception. We therefore hold that in exercising its broad discretion to determine whether a nondisclosure of evidence is substantially justified or harmless for purposes of a Rule 37(c)(1) exclusion analysis, a district court shоuld be guided by the following factors: (1) the surprise to the party against whom the evidence would be offered; (2) the ability of that party to cure the surprise; (3) the extent to which allowing the evidence would disrupt the trial; (4) the importance of the evidence; and (5) the non-disclosing party’s explanation for its failure to disclose the evidence.
2.
We recоgnize that two published opinions of this court have stated that in “determining what sanctions to impose under Rule 37,” a district court must consider four factors: “(1) whether the non-complying party acted in bad faith, (2) the amount of prejudice that noncompliance caused the adversary, (3) the need for deterrence of the particular sort of non-compliance, and (4) whether less drastic sanctions would have been effective.”
Anderson v. Found. for Advancement, Educ. & Employment of Am. Indians,
In
Anderson,
we affirmed a default judgment sanctiоn against a party that repeatedly failed to comply with discovery orders requiring it to produce requested documents — violations governed by Fed. R.Civ.P. 37(b).
See Anderson,
In contrast to Rule 37(c)(1) — which generally requires exclusion of evidence that a party seeks to offer but has failed to disclose, see supra note 2 — Rule 37(b) provides district courts with greater discretion in selecting one or more appropriate sanctions. See Fed.R.Civ.P. 37(b)(2) (stating that when parties fail to obey discovery orders, courts “may make such orders in regard to the failure as are just,” and listing several possible sanctions). Thus, while the exclusion analysis under Rule 37(c)(1) is limited by the specific language of that provision, Rule 37(b) allows district courts to consider a broader range of factors, including bad faith, in determining which sanction(s) to impose.
For this reason, the four-factor -test recited in
Anderson
and
Belk,
which includes
*598
bad faith, does not control the detеrmination of whether to exclude evidence under Rule 37(c)(1). Indeed, the most recent published decision of this court applying Rule 37(c)(1) did not consider whether the nondisclosing party acted in bad faith, but instead focused solely on whether the failure to disclose was substantially justified or harmless.
See Nelson-Salabes, Inc.,
We also acknowledge that other circuits interpreting Rule 37(c)(1) apply various tests that either do or do not include bad faith as a consideration.
Compare Nicholas v. Pa. State Univ.,
B.
Because the district court here properly relied on the five factors discussed above in deciding the exclusion issue, we now turn to the application of these factors. The district court found that Sherwin-Williams was surprised by Byrnes’ third opinion, because both at his deposition and in his August 6, 2001 supplemental report, Byrnes indicated that he had completed his opinions. In addition, the court explained that Sherwin-Williams was unable to cure this surprise. Noting that “the ability to simply cross-examine an expert concerning a new opinion at trial is not the ability to cure,” the court emphasized that “rules of expert disclosure are designed to allow an opponent to examine an expert opinion for flaws and to develop counter-testimony through that party’s own experts. Such was not possible here.” J.A. 1593. The district court also found that granting a continuance to accommodate Byrnes’ third opiniоn would have significantly disrupted the trial, because “witnesses from distant places had testified and if the case were continued and tried again, much of the parties’ trial preparation would be rendered obsolete.” Id.
Regarding Southern States’ explanation for Byrnes’ undisclosed opinion — alleged delays by Sherwin-Williams in producing the paint formula — the court explained that Southern States “cannot escape that it failed to file a motion to compel twenty days after it knew Sherwin-Williams would not produce the formula.” Id. More important to the district court, however, Southern States could not “explain why it did not supplement its discovery responses when it knew of ... Byrnes’ new, third opinion formed on the Mondаy the trial began.” Id. Finally, the court recognized that Byrnes’ new opinion concerning an alleged defect in the paint formula was important evidence. However, the court explained that “this factor must be viewed from the perspective of both parties”: “The fact that the expert’s testimony regarding the paint formula might have been helpful tо [Southern States’] case in the *599 eyes of the jury also points out why it should have been disclosed in a timely manner to [Sherwin-Williams].” Id. at 1593-94.
We believe that the district court correctly determined that a balancing of the five factors discussed above weighed in favor of excluding Byrnes’ third opinion. Thus, the district court did not abuse its discretion in excluding this opinion based on Rule 37(c)(1). 5
III.
For the reasons set forth above, we affirm the judgment of the district court.
AFFIRMED.
Notes
. Southern States claims that the information Byrnes communicated to counsel on the Monday evening of trial week was, at that point, merely a "hypothesis.” Br. for Plaintiff-Appellant at 6. According to Southern States, Byrnes tested that hypothesis the following day, and he confirmed his new "opinion” tо counsel Tuesday night. Id. However, Southern States also made this argument to the district court in its motion for a new trial, and the district court apparently did not credit it, finding that Byrnes’ new opinion was "formulated on the Monday the trial began.” J.A. 1591. Indeed, after Byrnes disclosed his new opinion during voir dire, Southern States' counsel repeatedly stated to the court that Byrnes had сommunicated the new opinion to counsel on Monday. Given these admissions, we will not disturb the finding of the district court that Byrnes formulated his new opinion that Monday.
. In its entirety, Rule 37(c)(1) reads:
A party that without substantial justification fails to disclose information required by Rule 26(a) or 26(e)(1), or to amend a prior response to discovery as required by Rule 26(e)(2), is not, unless such failure is harmless, permitted to use as evidence at a trial, at a hearing, or on a motion any witness or information not so disclosed. In addition to or in lieu of this sanction, the court, on motion and after affording an opportunity to be heard, may impose other appropriate sanctions. In addition to requiring payment of reasonable expenses, including attorney’s fees, caused by the failure, these sanctions may include any of the actions authorized under Rule 37(b)(2)(A), (B), and (C) [relating to failure to comply with discovery orders] and may include informing the jury of the failure to make the disclosure.
The Rule 37(c) advisory committee notes emphasize that the "automatic sanction” of exclusion "provides a strong inducement for disclosure of material that the disclosing party would expect to use as evidence.” Fed. R.Civ.P. 37(c) advisory committee note (1993). The alternative sanctions referenced in the rule are primarily intended to apply when a party fails to disclose evidence helpful to an opposing party. See 7 James Wm. Moore et al., Moore’s Federal Practice §§ 37.60[2][b], 37.61 (3d ed.2002). This is because "[preclusion of evidence is not an effective incentive to compel disclosure of information that, being supportive of the position of the opposing party, might advantageously be concealed by the disclosing party.” Fed.R.Civ.P. 37(c) advisory committee note (1993).
.
Rambus
noted the discrepancy between
Burlington Insurance
and another unpublished decision of this court addressing the standards for excluding evidence under Rule 37(c)(1).
See Tritchler v. Consolidation Coal Co.,
. The district court stopped short of making a finding of bad faith.
. We also reject Southern States' claim that the district court should have ordered a new trial because Byrnes’ third opinion constituted newly discovered evidence. Because Southern States learned of this evidence
during
trial, it cannot be considered "newly discovered” for purposes of a post-trial motion.
See Boryan v. United States,
