Evidence: Privileges

In evidence law, privileges are deliberate exceptions to the general rule that courts should hear all relevant, reliable information. A privilege gives someone a legally protected right to refuse to disclose certain communications or to prevent another person from disclosing them. The common thread is protection from compelled disclosure, even when the information is highly probative.

Privileges are not designed to help a party “win.” They exist to serve broader social interests, such as encouraging candid legal advice, protecting intimate family relationships, and promoting effective medical treatment. Because privileges can keep important facts from the factfinder, courts typically interpret them narrowly and apply them only when the required elements are met.

What follows is a practical, structured guide to major privileges commonly tested and commonly litigated: attorney client privilege, spousal privileges (testimonial and communications), doctor patient privilege, and the work product doctrine.

Why privileges matter in litigation

Modern litigation runs on information. Parties use subpoenas, depositions, interrogatories, and document requests to compel production. Privileges create a hard stop. If a communication is privileged and the privilege has not been waived, it is generally inadmissible and also protected from discovery.

Privileges influence how professionals document decisions, how families communicate under stress, and how organizations investigate problems. They also shape courtroom dynamics because a privilege can prevent the jury from hearing what looks like the most direct proof.

Core concepts: communication, confidentiality, and waiver

Most privileges share three recurring questions:

Was it a protected communication?

Privileges generally protect communications, not underlying facts. A client cannot be forced to reveal what they told their lawyer, but the client can usually be forced to reveal the facts of what happened if those facts are known from sources independent of the privileged conversation.

Was it intended to be confidential?

Confidentiality is central. If the communication was made in the presence of unnecessary third parties, or later disclosed broadly, the protection may be lost. Limited disclosures to those necessary to further the purpose of the relationship often do not destroy confidentiality, but careless sharing can.

Was there a waiver?

Privileges can be waived expressly (by consenting to disclosure) or implicitly (by conduct inconsistent with maintaining confidentiality). Waiver issues arise frequently when parties partially disclose information to gain a tactical advantage, or when communications are forwarded, copied widely, or discussed outside the protected relationship.

Attorney client privilege

Attorney client privilege protects confidential communications between a lawyer and a client made for the purpose of seeking or providing legal advice.

What it covers

At its core, the privilege covers:

• Communications (oral, written, and often electronic)
• Between attorney and client (including certain agents necessary for the legal consultation)
• Made in confidence
• For the purpose of legal advice or representation

This is why, for example, a company can consult counsel about regulatory risk and keep those communications out of discovery, provided the communications are legal in nature and maintained as confidential.

What it does not cover

Common limitations include:

• Underlying facts: A client cannot shield facts by telling them to a lawyer.
• Business advice: If the lawyer is acting primarily as a business negotiator or executive rather than legal counsel, the communication may fall outside the privilege.
• Communications intended for disclosure: Drafts meant to be filed publicly or statements prepared for third parties may not remain privileged in the same way.

Practical example

If a client emails their attorney, “Here are the timeline and documents. What are my legal risks?” that communication is typically privileged. If the same email is forwarded to a friend or a public relations consultant who is not necessary to legal representation, the confidentiality element may be compromised and privilege may be waived.

Spousal privileges: testimonial vs communications

Evidence law recognizes two distinct protections involving spouses, and they operate differently. The policy goal is to protect the marital relationship, but the privileges are not identical in scope or in who controls them.

Spousal testimonial privilege

The spousal testimonial privilege (in jurisdictions that recognize it) generally allows a spouse to refuse to testify against the other spouse in a criminal case. It is a privilege about testimony, not just communications. Its defining features include:

• It applies only during a valid marriage.
• It covers compelled adverse testimony, not necessarily voluntary testimony.
• It typically belongs to the witness spouse, meaning the witness spouse can choose whether to testify.

The practical effect is that the state may be barred from forcing a spouse onto the stand to provide incriminating testimony against their spouse.

Marital communications privilege

The marital communications privilege protects confidential communications made between spouses during the marriage. Key features:

• It protects communications, not all observations or acts.
• It typically requires that the communication was intended to be confidential.
• In many frameworks, it survives the end of the marriage as to communications made during the marriage.

This privilege is frequently litigated around questions like whether a statement was truly a “communication,” whether it was confidential, and whether a third party’s presence destroyed the privilege.

Practical example

A spouse may be able to refuse to reveal a private confession made in the home. But if the spouse observed the other spouse commit an act, that observation may not be a “communication” and may be outside the privilege, depending on the jurisdiction and the circumstances.

Doctor patient privilege

Doctor patient privilege protects confidential communications between a patient and a medical provider made for the purpose of diagnosis or treatment. The public interest is straightforward: patients need to be candid to receive proper care, and fear of disclosure could deter people from seeking treatment or sharing sensitive information.

What it typically covers

• Statements about symptoms, history, and conditions shared for treatment
• Medical evaluations and records tied to diagnosis and care
• Communications intended to be confidential within the treatment context

Common pressure points

Medical privacy often collides with litigation needs. Doctor patient privilege issues arise in personal injury cases, employment disputes, and criminal matters where health is relevant. A frequent issue is whether a patient has put their medical condition “at issue” in the litigation, which can narrow or waive protection for relevant medical information.

Practical example

A plaintiff who sues for physical injury and emotional distress may open the door to medical records relevant to those claims. Even then, disputes often center on scope: relevant treatment records versus a sweeping request for unrelated history.

Work product doctrine

Work product is closely related to attorney client privilege but distinct in purpose and operation. It protects materials prepared in anticipation of litigation, particularly those reflecting legal strategy, mental impressions, and investigative planning.

What it covers

Work product generally includes:

• Attorney notes and memos
• Litigation strategy documents
• Interview outlines and summaries
• Investigator reports created at counsel’s direction for litigation

The key concept is that adversarial systems depend on allowing each side to prepare their case without handing the playbook to the other side.

Ordinary vs opinion work product

Although terminology varies, a useful practical distinction is:

• Ordinary (fact) work product: materials prepared for litigation that contain factual information, potentially discoverable in limited circumstances if the requesting party shows strong need and lack of alternatives.
• Opinion work product: mental impressions, legal theories, and strategy, which receive heightened protection and are rarely compelled.

Practical example

If counsel interviews a witness and writes a summary with comments like “witness seems unreliable” and “key impeachment points,” those mental impressions are classic opinion work product. A party seeking the underlying facts is usually expected to interview the witness directly rather than obtain counsel’s notes.

Managing privilege in real practice

Privilege protection is not automatic. It is maintained through disciplined handling of communications and records.

Build confidentiality into routines

• Limit distribution of legal advice to those who need to know.
• Separate legal advice from business discussions when possible.
• Treat sensitive communications as confidential from the start.

Document with intent

Professionals should assume that anything not privileged may be discoverable later. Clear labeling does not create privilege by itself, but careful documentation of purpose and context can help demonstrate why a communication is protected.

Watch for waiver

Forwarding an attorney email, repeating a spouse’s confidential statement to friends, or producing medical records voluntarily can create waiver arguments. Selective disclosure is especially risky because it invites claims that fairness requires broader disclosure.

Conclusion

Privileges are powerful tools that shape the flow of information in court. Attorney client privilege protects legal counsel and candid consultation. Spousal privileges, both testimonial and communications, safeguard core marital interests in different ways. Doctor patient privilege supports truthful treatment relationships. The work product doctrine preserves the integrity of litigation preparation.

For lawyers, clients, and litigants, the practical lesson is consistent: privileges protect confidential communications and litigation preparation only when they are handled carefully. Once confidentiality is broken or a privilege is waived, the protection may be impossible to restore.