Discovery (law)

Discovery, in the law of common law jurisdictions, is a pre-trial procedure in a lawsuit in which each party, through the law of civil procedure, can obtain evidence from the other party or parties by means of discovery devices such as interrogatories, requests for production of documents, requests for admissions and depositions. Discovery can be obtained from non-parties using subpoenas. When a discovery request is objected to, the requesting party may seek the assistance of the court by filing a motion to compel discovery.


Discovery evolved out of a unique feature of early equitable pleading procedure before the English Court of Chancery: among various requirements, a plaintiff's bill in equity was required to plead "positions." These were statements of evidence that the plaintiff assumed to exist in support of his pleading and which he believed lay within the knowledge of the defendant. They strongly resembled modern requests for admissions, in that the defendant was required to plead only whether they were true or false. At some point between the reign of Elizabeth I and the late seventeenth century, positions were gradually replaced by interrogatories—written questions which the defendant was required to truthfully respond to under oath in his answer to the bill based on information within his own personal knowledge as well as documents in his possession. But back then, interrogatories could only elicit admissible evidence and could only request evidence in support of the plaintiff's case, not either side's case. Even worse, this was purely a one-way procedure, because interrogatories could only be pleaded as part of a bill. A defendant who needed to obtain evidence in support of his defenses had to file a cross-bill against the plaintiff to plead his own interrogatories.
Discovery did not exist at common law, but its availability in equity attracted litigants in actions at law. They began to file bills in equity to obtain discovery in aid of actions at law. This led to another innovation in the mid-15th century: the bill to perpetuate testimony of a potential witness. This was for witnesses whose advanced age or poor health implied they would not survive to testify at the trial of an action at law. In this type of proceeding, the parties merely pleaded written interrogatories which a master or a lay commissioner would read out loud to the witness in a closed proceeding without parties or counsel present. The witness's oral answers were written down by the master or lay commissioner in summary form as if they had been delivered as a single continuous narrative ; the actual sequence of questions and answers was not transcribed verbatim like a modern deposition. The resulting document was then sealed and not revealed or "published" to parties or counsel until shortly before the trial in which it was to be used.
This procedure for ex parte out-of-court pretrial examinations came to be called a "deposition." It continued to be used as an evidence preservation device in aid of actions at law, but it also became the standard method for developing the factual record to be used in courts of equity as derived from the knowledge of third-party witnesses. The master or commissioner necessarily performed a limited factfinding function when summarizing testimony in narrative form to be relied upon by the Lord Chancellor in lieu of live testimony in open court. As implied by the secret nature of the proceedings and the absence of parties and counsel, equity's factfinding process was fundamentally inquisitorial, and not adversarial. It is generally believed that this came about because the early Chancellors and the masters who assisted them were clerics with training in Roman and canon law, and therefore had some knowledge of the inquisitorial system as it functioned in ecclesiastical courts. The secrecy of the proceedings was thought to be absolutely essential to prevent perjury and witness tampering; the witnesses would thereby be forced to testify from memory alone, and the parties could not use the facts disclosed in testimony to guide their discovery or litigation strategy. Consistent with this inquisitorial view, there were also prohibitions on repeat testimony and on additional testimony after publication. Rather, the witnesses would testify independently of each other before publication, then at the moment of publication, all would be revealed, and the parties would make their arguments to the Chancellor on that cold record. It is this procedure to which the United States Congress was referring in an 1802 law providing that "in all suits in equity, it shall be in the discretion of the court, upon the request of either party, to order the testimony of the witnesses therein to be taken by depositions."
The next major development occurred under the supervision of Chancellor James Kent of the New York Court of Chancery during the early 19th century. He was trying to respond to the obvious defect of traditional depositions: since parties could not adjust their questions on the fly, they had to propound broadly drawn interrogatories, and in turn elicited "long and complicated accounts" of the facts that were difficult for masters to summarize in writing. Therefore, Kent allowed New York masters to actively engage in oral examination of witnesses, and he also allowed parties and counsel to be present when such examinations were conducted. Kent's innovations spread into American federal practice in 1842 when the U.S. Supreme Court amended the Federal Equity Rules to allow masters in equity suits in federal courts to conduct oral examinations of witnesses. However, with the parties and counsel now present to help guide the course of the master's oral examination of the witness, it was inevitable that counsel would insist on taking over the examination itself. Also, their presence meant the proceedings were no longer secret.

Major reforms enacted in New York in the late 1840s and in England in the early 1850s laid the foundation for the rise of modern discovery by imposing a clear separation between pleadings and discovery as distinct phases of procedural law. Discovery devices could now be invoked independently of the pleadings. The New York reforms went much farther, by directly merging common law and equity procedure, and by expressly authorizing pretrial oral examinations of both opposing parties and third-party witnesses, the basis of the modern deposition. In fact, the New York code of civil procedure went so far as to abolish written interrogatories. A major flaw, though, of the New York code of civil procedure was that it only allowed parties to seek discovery on issues on which they would have the burden of proof at trial. This caused lawyers for defendants to plead fictional defenses in answers, because they still could not directly pursue discovery into the plaintiff's claims.
In 1861, Rule 67 of the Federal Equity Rules was amended to make deposition by oral examination the regular method of taking evidence in equity in federal courts; taking witness testimony by written interrogatories was now the exception. Although depositions were still taken in front of court-appointed examiners, their role had been reduced to the preparation of summary narratives to be relied upon as evidence by the court. In 1892, Rule 67 was again amended to require the preparation of an exact transcript. Subsequent amendments in 1893 and 1912 eliminated the deposition's traditional role as an equitable factfinding device by first allowing and then requiring oral testimony in open court in trials of federal suits in equity, thereby reducing the deposition to its modern role in American civil procedure as a discovery and evidence preservation device.
In 1938, the promulgation of the Federal Rules of Civil Procedure created for the first time a comprehensive discovery system in U.S. federal courts. The FRCP authorized broad discovery into "any matter, not privileged, which is relevant to the subject matter in the pending action, whether relating to the claim or defense of" either party. Due to the influence of progressive law professor Edson R. Sunderland, an enthusiastic proponent of broad discovery, the FRCP expressly authorized the complete family of discovery methods familiar to American litigators today. What made the FRCP so revolutionary was that although many state governments had regularly allowed one or more methods of discovery, no one state nor the federal government had ever attempted to allow litigators to use all of them, as Sunderland frankly admitted to the Advisory Committee that drafted the FRCP. As a result, the United States has the broadest discovery system in the world.
After this system weathered blistering criticism for many decades, the United States retreated somewhat from broad discovery by expressly incorporating a proportionality requirement into the scope of discovery in the version of the FRCP that went into effect on December 1, 2015.

United States

Under the law of the United States, civil discovery is wide-ranging and may seek disclosure of information that is reasonably calculated to lead to the discovery of admissible evidence. This is a much broader standard than relevance, because it contemplates the exploration of evidence which might be relevant, rather than evidence which is truly relevant. Certain types of information are generally protected from discovery; these include information which is privileged and the work product of the opposing party. Other types of information may be protected, depending on the type of case and the status of the party. For instance, juvenile criminal records are generally not discoverable, peer review findings by hospitals in medical negligence cases are generally not discoverable and, depending on the case, other types of evidence may be non-discoverable for reasons of privacy, difficulty or expense in complying and for other reasons. Electronic discovery or "e-discovery" refers to discovery of information stored in electronic format.
In practice, most civil cases in the United States are settled after discovery. After discovery, both sides often are in agreement about the relative strength and weaknesses of each side's case and this often results in either a settlement or summary judgment, which eliminates the expense and risks of a trial.
Discovery is also available in criminal cases. Under the rule set forth in Brady v. Maryland, the prosecutor is obligated to provide to the defendant any information that is exculpatory or potentially exculpatory, without any request by the defense. Further discovery is available if initiated by the defendant. For example, a discovery demand might be for production of the names of witnesses, witness statements, information about evidence, a request for opportunity to inspect tangible evidence, and for any reports prepared by expert witnesses who will testify at trial.
If a defendant in a criminal case requests discovery from the prosecution, the prosecutor may request reciprocal discovery. The prosecutor's right to discovery is deemed reciprocal as it arises from the defendant's request for discovery. The prosecutor's ability to obtain discovery is limited by the defendant's Fifth Amendment rights, specifically the defendant's constitutional protection against self-incrimination.

Federal law

is unique compared to other common law countries. In the United States, discovery is mostly performed by the litigating parties themselves, with relatively minimal judicial oversight. The Federal Rules of Civil Procedure guide discovery in the U.S. federal court system. Most state courts follow a similar version based upon the FRCP, Chapter V "Depositions & Discovery" .
According to the Federal Rules of Civil Procedure, the plaintiff must initiate a conference between the parties after the complaint was served to the defendants, to plan for the discovery process. The parties should attempt to agree on the proposed discovery schedule, and submit a proposed Discovery Plan to the court within 14 days after the conference. After that, the main discovery process begins which includes: initial disclosures, depositions, interrogatories, request for admissions and request for production of documents. In most federal district courts, the formal requests for interrogatories, request for admissions and request for production are exchanged between the parties and not filed with the court. Parties, however, can file motion to compel discovery if responses are not received within the FRCP time limit. Parties can file a motion for a protective order if the discovery requests become unduly burdensome or for purpose of harassment.
In federal criminal prosecutions, discovery rights originate from a number of important Supreme Court decisions and statutes, the most important of which are,
The formal discovery process for federal criminal prosecutions is outlined in the Federal Rules of Criminal Procedure, Rule 16.

District of Columbia

The District of Columbia follows the federal rules, with a few exceptions. Some deadlines are different, and litigants may only resort to the D.C. Superior Court.
Forty interrogatories, including parts and sub-parts, may be propounded by one party on any other party.
There is no requirement for a "privilege log": federal Rule 26 was not adopted by the D.C. Superior Court.
Where above is stated "litigants may only resort to the D.C. Superior Court" upon correction is found according to the District of Columbia Superior Court Rules of Civil Procedure Section 73Judicial Review and Appeal which states: "Judicial review of a final order or judgment entered upon direction of a hearing commissioner is available on motion of a party to the Superior Court judge designated by the Chief Judge to conduct such reviews...After that review has been completed, appeal may be taken to the District of Columbia Court of Appeals." This rule basically implies that in a civil action, if a hearing commissioner is authorized by all parties to conduct the proceedings instead of a judge, upon a request for a review or appeal, the motion must first be reviewed by a Superior Court judge to the same standard as a motion for appeal on a Superior Court Judge to the Court of Appeals, but the right to appeal to the higher courts still remains.

State law

Many states have adopted discovery procedures based on the federal system; some closely adhere to the federal model, others not so closely. Some states take an entirely different approach to discovery. Many states have adopted the Uniform Interstate Depositions and Discovery Act to provide uniform process when discovery is to be done out of state.


In Alaska criminal courts, discovery is governed by Rule of Criminal Procedure 16. The scope of discovery is broad and includes much more than is required by Brady v. Maryland, 373 U.S. 83. The discovery process is intended to provide adequate information for informed pleas, to expedite trial, minimize surprise, afford an opportunity for effective cross-examination, and meet the requirements of due process. To the extent possible, discovery prior to trial should be as full and free as possible, consistent with protection of persons, effective law enforcement, and the adversarial system.
A prosecuting attorney is required to disclose to the accused the following material, and to make it available for inspection and copying: names and addresses of witnesses, written or recorded statements of the accused, written or recorded statements of a co-defendant, any books, papers, documents, photographs or tangible objects with the prosecutor intends to use at trial, any prior criminal convictions of the defendant or any witness. In practice, this means that criminal defendants in Alaska are able to review any police report, lab report, audio/video recordings, witness statements, and more, before they proceed to trial. Most defendants will also have this material far enough in advance to have reviewed it before making a decision about any possible plea deal.


In California state courts, discovery is governed by the Civil Discovery Act of 1986, as subsequently amended. A significant number of appellate court decisions have interpreted and construed the provisions of the Act.
California written discovery generally consists of four methods: Request for Production of Documents, Form Interrogatories, Special Interrogatories, and Requests for Admissions. Responses to California discovery requests are not continuing: the responding party only needs to respond with the facts as known on the date of the response, and is under no obligation to update its responses as new facts become known. This causes many parties to reserve one or two interrogatories until the closing days of discovery, when they ask if any of the previous responses to discovery have changed, and then ask what the changes are. California depositions are not limited to one day, and objections must be made in detail or they are permanently waived. A party may only propound thirty-five written special interrogatories on any other single party unless the propounding party submits a "declaration of necessity". No "subparts, or a compound, conjunctive, or disjunctive question" may be included in an interrogatory. However, "form interrogatories" which have been approved by the state Judicial Council do not count toward this limit. In addition, no "preface or instruction" may be included in the interrogatories unless it has been approved by the Judicial Council; in practice, this means that the only instructions permissible with interrogatories are the ones provided with the form interrogatories.


The use of discovery has been criticized as favoring the wealthier side in a lawsuit, by enabling parties to drain each other's financial resources in a war of attrition. For example, one can make information requests that are potentially expensive and time-consuming for the other side to fulfill; respond to a discovery request with thousands of documents of questionable relevance to the case; file requests for protective orders to prevent the deposition of key witnesses; and take other measures that increase the difficulty and cost of discovery. In 1983, the Advisory Committee on Civil Rules attached a Committee Note to Rule 26 of the FRCP that cautioned federal courts to "prevent use of discovery to wage a war of attrition or as a device to coerce a party, whether financially weak or affluent," then had to repeat and stress that exact same text in the 2015 Committee Note.
It has been argued that although the goal of discovery is to level the playing field between the parties, the discovery rules instead create a multi-level playing field that favors the party that is in control of the information needed by the other party. Instead of encouraging discovery, the rules are described as encouraging lawyers to find new ways to manipulate and distort or conceal information.
Some tort reform supporters make a similar accusation, that discovery is used by plaintiffs' lawyers to impose costs on defendants in order to force settlements in unmeritorious cases to avoid the cost of discovery. However, others argue that discovery abuse is an exaggerated concept, that discovery works well in most cases, and exaggeration of American litigiousness and its cost result in confusion within the justice system.
As implemented in 1938, the modern American discovery scheme granted powers directly to private parties and their counsel which are "functionally equivalent" to the power to issue self-executing administrative subpoenas. This is why civil law countries strongly dislike and oppose American discovery: they regard broad discovery in the hands of private parties as destructive of the rule of law because from their perspective, the result amounts to "a private inquisition." Civil law countries see the underlying objectives of discovery as properly monopolized by the state in order to maintain the rule of law: the investigative objective of discovery is the prerogative of the executive branch, and insofar as discovery may be able to facilitate the creation of new rights, that is the prerogative of the legislative branch.

Electronic discovery

Electronic discovery, also known as ediscovery, involves the discovery of electronic data and records. It is important that data obtained through ediscovery be reliable, and therefore admissible.
Currently the two main approaches for identifying responsive material on custodian machines are:
where physical access to the organisations network is possible - agents are installed on each custodian machine which push large amounts of data for indexing across the network to one or more servers that have to be attached to the network or
for instances where it is impossible or impractical to attend the physical location of the custodian system - storage devices are attached to custodian machines and then each collection instance is manually deployed.
In relation to the first approach there are several issues:
New technology is able to address problems created by the first approach by running an application entirely in memory on each custodian machine and only pushing responsive data across the network. This process has been patented and embodied in a tool that has been the subject of a conference paper.
In relation to the second approach, despite self-collection being a hot topic in eDiscovery, concerns are being addressed by limiting the involvement of the custodian to simply plugging in a device and running an application to create an encrypted container of responsive documents ]

In England and Wales

The discovery process in the jurisdiction of England and Wales has been known as "disclosure" since the reforms to civil procedure introduced by Lord Justice Woolf in 1999.
Disclosure is for many types of cause of action governed by Part 31 of the Civil Procedure Rules, and its linked Practice Direction 31B. As in the United States, certain documents are privileged, such as letters between solicitors and experts.
The usual forms of discovery are general discovery and specific discovery since parties in issue are unlikely to reach agreements as to what ought to be disclosed. This reflects in the current discovery rules which put emphasis on compliance of time limit, rules on service, proper list of documents and rules on privileges set out in Part 31 of CPR and PD 31B. Once a party properly conducts general discovery process in accordance with discovery rules and procedures, documents are deem discoverable, i.e. documents are available for inspection. Inspectionability refers to procedural and legal elements: the former concerns clerical production of document; the latter concerns the relevance test and linkage test.