Definition
Qui tam (from the Latin qui tam pro domino rege quam pro se ipso, meaning "who as well for the king as for himself") is a procedural device allowing a private individual to bring a civil lawsuit on behalf of the government, seeking recovery of penalties or damages for fraud or other statutory violations, and to retain a share of any recovery obtained.
In modern American law, qui tam actions arise most prominently under the federal False Claims Act (31 U.S.C. §§ 3729–3733), which imposes civil liability on persons who submit false or fraudulent claims for payment to the federal government. The private plaintiff who files the action is called a relator. The government may intervene and take over the case; if it does not, the relator may proceed independently. Either way, the relator receives a statutory percentage of the final recovery — typically 15 to 30 percent, depending on the government's level of participation — with the remainder going to the United States Treasury.
The essential structure: a statute creates a penalty or liability; a private party with knowledge of the violation brings suit in the government's name (and their own); the statute divides any recovery between the relator and the government.
Common Language
Wiktionary: "A writ whereby a private individual who assists a prosecution can receive all or part of any penalty imposed."
Webster's 1913: Not independently defined. The phrase appears only as a component of compound legal terms in period legal dictionaries.
The common usage capture is incomplete in two ways. First, qui tam actions are civil, not criminal — calling the relator someone who "assists a prosecution" suggests a criminal context that does not apply. Second, the modern legal mechanism is far more structured than the writ framing implies: the relator does not merely assist; they initiate, conduct (if the government declines), and bear litigation risk. The gap between the lay shorthand and the legal reality matters for research because historical sources use "informer" language that carries criminal connotations the doctrine does not actually require.
Common Confusion
Qui tam is frequently conflated with whistleblower protection statutes. These are distinct. Whistleblower statutes protect employees from retaliation for reporting misconduct; qui tam provisions create an affirmative cause of action allowing a relator to sue on the government's behalf. A person may be both a whistleblower and a qui tam relator simultaneously — particularly in False Claims Act cases — but the legal theories, remedies, and procedural rules are separate. Researchers should not assume that a source discussing "whistleblower" law addresses qui tam standing, damages caps, or government intervention rights.
Qui tam is also distinct from a bounty program. A bounty is an administrative reward paid by an agency (such as the SEC's whistleblower program under Dodd-Frank); a qui tam action is a civil lawsuit in federal court with discovery, pleading requirements, and a sealed filing period. The recoveries and procedural postures differ substantially.
Why It Matters in Research
The modern relevance of qui tam is almost entirely shaped by the False Claims Act's 1986 amendments, which dramatically expanded relator rights and recovery percentages and lifted a prior-public-disclosure bar that had gutted the mechanism. Pre-1986 sources — including the historical dictionary entries reproduced here — describe a doctrine that functioned quite differently in practice. Researchers working with pre-amendment case law or commentary should treat those sources as historical background, not as current doctrine.
Jurisdictional complexity is significant. Many states have enacted their own false claims statutes with qui tam provisions, and their rules — on standing, the government's intervention period, the sealed complaint requirement, and the relator share — vary. A researcher assuming federal False Claims Act rules apply to a state-law qui tam claim may miss critical procedural traps.
The corpus connection to healthcare fraud is the most heavily litigated qui tam context. The Law Mind Health Law & Bioethics Encyclopedia entry on the False Claims Act covers implied certification theory, the public disclosure bar, and the original source requirement — all of which are essential doctrinal neighbors to the basic qui tam mechanism and should be consulted alongside this entry.
In historical sources, the relator is often called the "informer" — a term that today carries connotations of criminal informing but in the qui tam context simply means the private party who brought the civil action. Do not read the historical "informer" label as indicating criminal procedure.
Historical Dictionary Support
The four dictionary sources here converge on the basic structure: a civil action, a statutory penalty, a split between the private plaintiff and the government (or another institution), and a Latin phrase identifying the plaintiff as acting both for the sovereign and for themselves. Burrill's is the most complete, tracing the name to the old Latin form of the pleading — QUI TAM pro domino rege... quam pro seipso — which explains the abbreviation used in modern practice.
Black's first and second editions are nearly identical in substance and reflect the pre-New Deal common law understanding: qui tam was a general common law procedural device available wherever a penal statute authorized it. The doctrine was not limited to fraud against the government; it applied to any statute that split a penalty between a private plaintiff and a public institution. This broader historical scope is mostly academic today — Congress has largely preempted the field through specific statutory schemes — but it matters for researchers tracing the doctrine's constitutional foundations.
Rapalje & Lawrence's treatment is skeletal, redirecting to the ACTION entry and citing early New Jersey and Georgia cases for procedural rules (such as the requirement that the action be brought in the name of the governor). These procedural relics have no modern analog but confirm that qui tam was a live procedural category in nineteenth-century American state courts, not merely a curiosity of English law.
What the historical sources miss entirely: the modern False Claims Act architecture, including the sealed complaint, the government's intervention election, the public disclosure bar, the original source exception, and the first-to-file rule. These are creatures of statute, not common law, and no pre-twentieth-century dictionary entry can illuminate them.
Jurisdictional Note
The federal False Claims Act is the dominant qui tam vehicle in American practice, but more than thirty states have enacted analogous statutes. California's False Claims Act and New York's False Claims Act are among the most active. State provisions may have different relator share percentages, shorter government intervention windows, and different pleading standards. Researchers should not assume federal doctrine maps onto state qui tam claims without checking the specific state statute.
Encyclopedia Cross-Reference
False Claims Act — Qui Tam Actions, Implied Certification, and Healthcare Fraud Enforcement (Law Mind Health Law & Bioethics Encyclopedia)