Discovery Law Explained

If you’re involved in a lawsuit, you may need to go through the discovery process. Discovery is where both sides exchange information relevant to the case. Here’s how it works.

What is discovery?

The discovery process is a legally required exchange of information between the two parties involved in a lawsuit.

The parties must exchange information about the evidence and witnesses they intend to use at trial.

Each party also has the right to obtain information they believe is relevant to the case that the other party may not intend to use.

Why does discovery happen?

Discovery is required by the state and federal rules of civil procedure.

While surprise witnesses and evidence make for great TV drama, trial by ambush is not part of the actual legal system.

Both parties generally have a right to know what evidence will be presented at trial. Any surprises are usually the result of a serious mistake by one of the lawyers.

Evidence not included in discovery is typically inadmissible. The judge may allow additional evidence with good cause such as it being newly discovered or it becoming relevant because of a witness saying something unexpected at trial.

Another reason for discovery is to allow each party to obtain evidence from the other. For example, an employee in an employment lawsuit generally has the right to obtain relevant records from his or her employer.

How does discovery work?

Each court has its own discovery procedures. Discovery is governed by:

  • Statutes

  • Case law

  • Rules of civil procedure

  • Judges’ rules

Statutes and case law define the general concepts of discovery and each party’s rights.

The rules of civil procedure further define the discovery process and the specifics of obtainable information and how to get it.

Each court or individual judge may also have discovery rules. These are often for procedural issues such as trial timelines or the process for raising discovery disputes.

The general process is that each party will send written requests for information. The other party will either provide the information, say they don’t have it, or raise a legal objection.

Any discovery disputes are resolved by a trial judge or a magistrate.

When does discovery happen?

Discovery generally happens after filing a lawsuit and before trial begins. If a party obtains new information during a trial or something unexpectedly becomes relevant, that information will typically become subject to discovery.

Parties may also exchange information before a lawsuit is filed. The purpose is to explore a possible settlement agreement.

Discovery may also be required as a contractual obligation. It may be required as part of an insurance claims process or if the parties agree to arbitrate or mediate a dispute.

Civil vs. Criminal Procedure

Criminal cases also have discovery, but the rules are different from civil procedure.

Prosecutors have an obligation to disclose exculpatory evidence often even if the defense doesn’t request it. Most of the information that a prosecutor has about a case is subject to discovery.

There are limited exceptions to what a defendant can get from the prosecution such as the personal information of a prosecution witness who needs protection.

Because of the Fifth Amendment, prosecutors have limited rights to discovery. They can generally receive things like witness lists, notice of physical evidence, and reports from defense expert witnesses.

Prosecutors can obtain other information via search warrants or subpoenaing witnesses.

What is a preservation request?

A preservation request is an early notice of a discovery request. The purpose is to make sure the other party preserves information that isn’t yet subject to discovery.

For example, a store’s surveillance camera footage might be relevant evidence in a slip and fall case. The store can refuse to provide the footage until a lawsuit is formally filed and discovery begins.

It’s common practice to only store video footage for so long due to storage limitations. Therefore, the video might be gone by the time the plaintiff can file the lawsuit.

A preservation request tells the store to override their usual procedures and make sure they save the video. If they don’t save the video after the preservation request, it can often be assumed as a matter of law that the video would have been bad for their case.

What are the types of discovery?

There are several types of discovery devices.


A deposition is an oral examination of a potential witness. It is usually video recorded and taken in the presence of a court reporter who creates a written transcript.

The purpose of the deposition is to discover what a witness might say at trial and if they have other useful information.

A deposition can also be used to impeach a witness if they say something different at trial than they did in the deposition.

Depositions can sometimes be introduced into evidence if a witness can’t appear at trial.

If a witness who isn’t a party in the case doesn’t want to attend a deposition, the requesting party may need to ask the judge to subpoena the witness.


Interrogatories are a set of written questions from one party to the other parties in the case.

Interrogatories obtain high-level information about the case and possible sources of additional information.

Answers to interrogatories are under oath.

Document Requests

The parties can also request relevant documents to a case.

For example, in a car accident case versus a trucking company, the plaintiff might request the truck driver’s logs to see if the driver skipped required rest periods.

Other Discovery Requests

The parties can also make other requests such as to inspect physical evidence, requiring a party to undergo a physical examination, or allowing an expert to review evidence for authenticity.

How do discovery objections work?

While discovery is generally a mandatory process, each party’s discovery rights may allow them to object to certain discovery requests.

The party receiving a request can notify the other party of their basis for objecting to the request. The requesting party might modify the request or further discuss it with opposing counsel.

If the opposing parties can’t resolve an objection, they may go to the trial judge for a ruling.

What are the grounds for objecting to discovery requests?

There are a number of possible reasons for objecting to discovery requests.

  • Certain documents may be covered by privilege such as attorney-client privilege

  • The request may not be relevant to the case

  • The request may be too broad

  • It may be too burdensome to respond compared to the importance of the information

  • The request may infringe upon private information not needed for the case

Judges typically prefer that the parties resolve objections by refining the requests to obtain needed information while avoiding other concerns. They also generally look poorly on parties who make frivolous objects to try to obstruct the discovery process.

What happens if a party refuses to respond to a discovery request?

A party can’t refuse to respond to a discovery request without a legally valid objection.

If a party refuses to respond, the judge has several options:

  • Issue an order compelling a response

  • Treating the refusal as an admission in favor of the requesting party

  • Finding the person who refuses to respond in contempt of court

Who pays for discovery?

The rules for paying the costs of discovery vary widely. Each party is generally expected to pay its own costs.

In some places, if a party makes a discovery request that will involve a substantial expense, such as a large document request, that party may be required to pay for the cost of processing that request.

If a case goes to trial, judges will sometimes award costs and legal fees to the prevailing party. This can depend on the type of case and local laws. In some places, costs and fees are only awarded when the evidence overwhelmingly favored one party.