Editing Class action (section)

=====Class certification under Rule 23=====
For the case to proceed as a class action and bind absent class members, the court must certify the class under Rule 23 on a motion from the party wishing to proceed on a class basis. For a class to be certified, the moving party must meet all of the criteria listed under Rule 23(a), and at least one of the criteria listed under Rule 23(b).<ref name=Rule23 />

The 23(a) criteria are referred to as '''numerosity''', '''commonality''', '''typicality''', and '''adequacy'''.<ref name="Bahe-Jachna_Page_57">{{cite book |last1=Bahe-Jachna |first1=Ruth A. |editor1-last=Greer |editor1-first=Marcy Hogan |title=A Practitioner's Guide to Class Actions |date=2010 |publisher=American Bar Association |location=Chicago |isbn=9781604429558 |pages=57-68 |chapter-url=https://books.google.com/books?id=d5oSx5C6YgIC&pg=PA57#v=onepage&q&f=false |access-date=May 8, 2025 |chapter=Chapter 3.B: Numerosity, Commonality, and Typicality}} (At p. 57.)</ref> '''Numerosity''' refers to the number of people in the class. To be certified, the class has to have enough members that simply adding each of them as a named party to the lawsuit would be impractical.<ref name=Rule23 /> There is no bright-line rule to determine numerosity, but classes with hundreds of members are generally deemed to be sufficiently numerous.<ref name="Bahe-Jachna_Page_58">{{cite book |last1=Bahe-Jachna |first1=Ruth A. |editor1-last=Greer |editor1-first=Marcy Hogan |title=A Practitioner's Guide to Class Actions |date=2010 |publisher=American Bar Association |location=Chicago |isbn=9781604429558 |pages=57-68 |chapter-url=https://books.google.com/books?id=d5oSx5C6YgIC&pg=PA58#v=onepage&q&f=false |access-date=May 8, 2025 |chapter=Chapter 3.B: Numerosity, Commonality, and Typicality}} (At p. 58.)</ref> To satisfy '''commonality''', there must be a common question of law and fact such that "determination of its truth or falsity will resolve an issue that is central to the validity of each one of the claims in one stroke".<ref>''[[Wal-Mart Stores, Inc. v. Dukes]]'', {{ussc|564|338|2011}}.</ref> The '''typicality''' requirement ensures that the claims or defenses of the named plaintiff are typical of those of everyone else in the class.<ref name=Rule23 /> Finally, '''adequacy''' requirement states that the named plaintiff must fairly and adequately represent the interests of the absent class members.<ref name=Rule23 />

Rule 23(b)(3) allows class certification if "questions of law or fact common to class members ''predominate'' over any questions affecting only individual members, and that a class action is ''superior'' to other available methods for fairly and efficiently adjudicating the controversy."<ref>{{cite journal |last1=Webber |first1=David H. |author-link=David H. Webber |title=The Plight of the Individual Investor |journal=Northwestern University Law Review |date=2012 |volume=106 |page=181 |url=https://scholarship.law.bu.edu/cgi/viewcontent.cgi?article=1034&context=faculty_scholarship |access-date=21 November 2019}} (Quoting Fed. R. Civ. P. 23(b)(3) (emphasis added)).</ref>