Unless otherwise limited by order of the court in accordance with these rules, the scope of discovery is as follows:
(a) In General. Parties may obtain discovery regarding any matter, not privileged, which is relevant to the subject matter involved in the pending action, whether it relates to the claim or defense of the party seeking discovery or to the claim or defense of any other party, including the existence, description, nature, custody, condition and location of any books, documents, electronically stored information, or other tangible things and the identity and location of persons having knowledge of any discoverable matter. It is not ground for objection that the information sought will be inadmissible at the trial if the information sought appears reasonably calculated to lead to the discovery of admissible evidence; nor is it ground for objection that the examining party has knowledge of the matters as to which discovery is sought.
(b) Insurance Agreements. A party may obtain discovery of the existence and contents of any insurance agreement under which any person carrying on an insurance business may be liable to satisfy part or all of a judgment which may be entered in the action or to indemnify or reimburse for payments made to satisfy the judgment. Information concerning the insurance agreement is not by reason of disclosure admissible in evidence at trial. For purposes of this paragraph, an application for insurance shall not be treated as part of an insurance agreement.
(c) Trial Preparation; Materials. Subject to the provisions of R. 4:10-2(d), a party may obtain discovery of documents, electronically stored information, and tangible things otherwise discoverable under R. 4:10-2(a) and prepared in anticipation of litigation or for trial by or for another party or by or for that other party's representative (including an attorney, consultant, surety, indemnitor, insurer or agent) only upon a showing that the party seeking discovery has substantial need of the materials in the preparation of the case and is unable without undue hardship to obtain the substantial equivalent of the materials by other means. In ordering discovery of such materials when the required showing has been made, the court shall protect against disclosure of the mental impressions, conclusions, opinions, or legal theories of an attorney or other representative of a party concerning the litigation.
A party may obtain without the required showing a statement concerning the action or its subject matter previously made by that party. Upon request, a person not a party may obtain without the required showing a statement concerning the action or its subject matter previously made by that person. If the request is refused, the person may move for a court order. The provisions of R. 4:23-1(c) apply to the award of expenses incurred in relation to the motion. For purposes of this paragraph, a statement previously made is (1) a written statement signed or otherwise adopted or approved by the person making it, or (2) a stenographic, mechanical, electronic, or other recording, or a transcription thereof, which is a substantially verbatim recital of an oral statement by the person making it and contemporaneously recorded.
(d) Trial Preparation; Experts. Discovery of facts known and opinions held by experts, otherwise discoverable under the provisions of R. 4:10-2(a) and acquired or developed in anticipation of litigation or for trial, may be obtained only as follows:
(1) A party may through interrogatories require any other party to disclose the names and addresses of each person whom the other party expects to call at trial as an expert witness, including a treating physician who is expected to testify and, whether or not expected to testify, of an expert who has conducted an examination pursuant to R. 4:19 or to whom a party making a claim for personal injury has voluntarily submitted for examination without court order. The interrogatories may also require, as provided by R. 4:17-4(a), the furnishing of a copy of that person's report. Discovery of communications between an attorney and any expert retained or specially employed by that attorney occurring before service of an expert's report is limited to facts and data considered by the expert in rendering the report. Except as otherwise expressly provided by R. 4:17-4(e), all other communications between counsel and the expert constituting the collaborative process in preparation of the report, including all preliminary or draft reports produced during this process, shall be deemed trial preparation materials discoverable only as provided in paragraph (c) of this rule.
(2) Unless the court otherwise orders, an expert whose report is required to be furnished pursuant to subparagraph (1) may be deposed as to the opinion stated therein at a time and place as provided by R. 4:14-7(b)(2). Unless otherwise ordered by the court, the party taking the deposition shall pay the expert or treating physician a reasonable fee for the appearance, to be determined by the court if the parties and the expert or treating physician cannot agree on the amount therefor. The fee for the witness's preparation for the deposition shall, however, be paid by the proponent of the witness, unless otherwise ordered by the court.
(3) A party may discover facts known or opinions held by an expert (other than an expert who has conducted an examination pursuant to R. 4:19) who has been retained or specially employed by another party in anticipation of litigation or preparation for trial and who is not expected to be called as a witness at trial only upon a showing of exceptional circumstances under which it is impractical for the party seeking discovery to obtain facts or opinions on the same subject by other means. If the court permits such discovery, it shall require the payment of the expert's fee provided for by R. 4:10-2(d)(2), and unless manifest injustice would result, the payment by the party seeking discovery to the other party of a fair portion of the fees and expenses which had been reasonably incurred by the party retaining the expert in obtaining facts and opinions from that expert.
(4) A party shall not seek a voluntary interview with another party's treating physician unless that party has authorized the physician, in the form set forth in Appendix XII-C, to disclose protected medical information.
(e) Claims of Privilege or Protection of Trial Preparation Materials.
(1) Information Withheld. When a party withholds information otherwise discoverable under these rules by claiming that it is privileged or subject to protection as trial preparation material, the party shall make the claim expressly and shall describe the nature of the documents, communications, or things not produced or disclosed in a manner that, without revealing information itself privileged or protected, will enable other parties to assess the applicability of the privilege or protection.
(2) Information Produced. If information is produced in discovery that is subject to a claim of privilege or of protection as trial preparation material, the party making the claim may notify any party that received the information of the claim and the basis for it. After being notified, a party must promptly return, sequester, or destroy the specified information and any copies it has and may not use or disclose the information until the claim is resolved. A receiving party may promptly present the information to the court under seal for a determination of the claim. If the receiving party disclosed the information before being notified, it must take reasonable efforts to retrieve it. The producing party must preserve the information until the claim is resolved.
(f) Claims that Electronically Stored Information is not Reasonably Accessible. A party need not provide discovery of electronically stored information from sources that the party identifies as not reasonably accessible because of undue burden or cost. On a motion to compel discovery or for a protective order, the party from whom discovery is sought shall demonstrate that the information is not reasonably accessible because of undue burden or cost. If that showing is made, the court nevertheless may order discovery from such sources if the requesting party establishes good cause, considering the limitations of R. 4:10-2(g). The court may specify conditions for the discovery.
(g) Limitation on Frequency of Discovery. The frequency or extent of use of the discovery methods otherwise permitted under these rules shall be limited by the court if it determines that: (1) the discovery sought is unreasonably cumulative or duplicative, or is obtainable from some other source that is more convenient, less burdensome, or less expensive; (2) the party seeking discovery has had ample opportunity by discovery in the action to obtain the information sought; or (3) the burden or expense of the proposed discovery outweighs its likely benefit, taking into account the needs of the case, the amount in controversy, the parties’ resources, the importance of the issues at stake in the litigation, and the importance of the proposed discovery in resolving the issues. The court may act pursuant to a motion or on its own initiative after reasonable notice to the parties.