United States: Supreme Court Rules That Rigorous Analysis Of Plaintiffs’ Damages Claims Is Required For Class Certification

Last Updated: April 10 2013
Article by Alden L. Atkins and Hannah Carrigg Wilson

The Supreme Court just issued an important decision reinforcing the need for rigorous analysis of class action plaintiffs' claims that damages can be determined on a class-wide basis. In Comcast Corp., et al. v. Behrend, et al., No. 11-864, 569 U.S. __ (March 27, 2013), a five-member majority of the Court reversed a judgment of the Third Circuit Court of Appeals upholding the certification of a class of antitrust plaintiffs. The Supreme Court held that the plaintiffs' damages model failed to show that plaintiffs could prove damages on a class-wide basis. The Court's decision makes clear that the rigorous analysis required by Wal-Mart Stores, Inc. v. Dukes, 131 S. Ct. 2541 (2011), applies to damages claims in antitrust class actions, even when it requires courts to inquire into the merits of the plaintiffs' claims.


The case arose from Comcast Corporation's practice of "clustering" its cable operations within certain geographic regions. Comcast's clustering strategy involved acquiring competitor cable providers in particular regions, including by swapping Comcast's systems in other regions in exchange for the competitor's systems in the region where it wanted a cluster of cable systems. In the Philadelphia region, Comcast entered into nine clustering transactions that increased its subscriber share in Philadelphia from 23.9 percent in 1998 to 69.5 percent in 2007. 264 F.R.D. 150, 156, n.8, 160 (E.D. Pa. 2010).

Certain subscribers of Comcast's cable television services filed a class action lawsuit, alleging that the clustering transactions violated Sections 1 and 2 of the Sherman Act by eliminating competition and increasing prices. The plaintiffs moved to certify a class under Federal Rule of Civil Procedure 23(b)(3), asserting four theories of antitrust impact. The plaintiffs relied on an expert to calculate damages for the entire class based on those four theories of antitrust harm. The expert admitted that the model incorporated damages from each theory, and that his model did not isolate damages for any one particular theory.

The district court rejected three of those theories for the purposes of the class action, and limited plaintiffs to "the theory that Comcast engaged in anticompetitive clustering conduct, the effect of which was to deter the entry of overbuilders in the Philadelphia" area. App. to Pet. for Cert. 192a-193a. Despite the fact that the plaintiffs' damages model combined all four theories of antitrust impact, the district court certified the class. The Third Circuit affirmed 2-1, with Judge Jordan issuing a strongly worded partial dissent.

The Supreme Court's Decision

The Supreme Court reversed and held that plaintiffs had failed to show that damages could be proven on a class-wide basis. Rule 23 establishes a two-step process for class certification: first, a court must determine if the requirements for all class actions under Rule 23(a) have been met; and, second, the court must determine if the class meets one of the requirements of Rule 23(b). For most antitrust cases, plaintiffs seek to certify the class under Rule 23(b)(3), which requires that questions of law or fact common to the class predominate over individual questions. The Court reiterated its prior holdings that courts must probe behind the pleadings before determining if the requirements of Rule 23(a) have been met. Importantly, the Court went on to say "[i]f anything, Rule 23(b)(3)'s predominance criterion is even more demanding than Rule 23(a)," Comcast, slip op. at 6, the subsection that was at issue in Wal-Mart. The Court said that Rule 23(b)(3) is an "adventuresome innovation" because "class action treatment is not as clearly called for" in "predominance" class actions compared to other types of class actions. Id. (quotation omitted).

The Supreme Court emphasized that the lower courts refused to examine the plaintiffs' damages model closely because they viewed it as going to the merits rather than to class certification. In reversing, the Supreme Court ruled that "[b]y refusing to entertain arguments against [plaintiffs'] damages model that bore on the propriety of class certification, simply because those arguments would also be pertinent to the merits determination, the Court of Appeals ran afoul of our precedents requiring precisely that inquiry." Id. at 6-7. The lower courts erred when they failed to link the plaintiffs' theory of antitrust harm to their damages model. Id. at 8. Because the damages model did not isolate the increased prices attributable to the lone permissible theory of liability, the plaintiffs had not shown that damages could be proven on a class-wide basis.

There are lower court decisions holding that individual questions of antitrust damages do not preclude class certification. The Court did not directly address that issue in Comcast. However, in a concluding footnote, it said that even if the plaintiffs' model had been limited to the accepted theory of antitrust harm, "it still would not have established the requisite commonality of damages unless it plausibly showed that the extent of overbuilding (absent deterrence) would have been the same in all counties, or that the extent is irrelevant to effect upon ability to charge supra-competitive prices." Id. at 10-11, n.6. The footnote suggests that plaintiffs must show that the extent of the harm is the same for all proposed class members.

The Comcast decision illustrates the burdens that plaintiffs bear when they seek to certify a class, particularly under Rule 23(b)(3). The lower courts have, in recent years, agreed that plaintiffs must prove antitrust impact — that class members have suffered some harm from the allegedly anticompetitive conduct — with common proof on a class-wide basis. In Comcast, the Supreme Court said the same is true of damages. Plaintiffs must be able to prove damages with common evidence for the entire class to ensure that common questions predominate. Citing the Court's Wal-Mart decision, the Court said that class certification questions would "frequently entail 'overlap with the merits of the plaintiff's underlying claim.'" Id. at 6. When performing that review, the Supreme Court instructed that courts must rigorously analyze the plaintiffs' damages model to determine whether it can prove damages for the anticompetitive conduct that is alleged.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

In association with
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement

Mondaq.com (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of www.mondaq.com

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about Mondaq.com’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to unsubscribe@mondaq.com with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


From time to time Mondaq may send you emails promoting Mondaq services including new services. You may opt out of receiving such emails by clicking below.

*** If you do not wish to receive any future announcements of services offered by Mondaq you may opt out by clicking here .


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to webmaster@mondaq.com.

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to EditorialAdvisor@mondaq.com.

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at enquiries@mondaq.com.

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at problems@mondaq.com and we will use commercially reasonable efforts to determine and correct the problem promptly.