In the course of the lawsuit, a party may serve on another party a request for admissions. The request can be aimed at facts and documents; depending on the state, it may also be aimed at legal opinions, conclusions and similar matters. The following pertains to California law.
The scope of requests to admit is quite broad. "[T]he fact that the request is for the admission of a controversial matter, or one involving complex facts, or calls for an opinion, is of no moment." Grace v. Mansourian, 240 Cal. App. 4th 523 (2015). The request may seek a legal conclusion, and may seek an admission that a party was negligent or that such negligence was a legal cause of the injuries. CCP Section 2033.010; Garcia v. Hyster Co., 28 Cal. App. 4th 724 (1994). A request for admission may properly be used to establish opinions relating to fact or the application of law to fact. Burke v. Superior Court, 71 Cal. 2d 276 (1969); Chodos v. Superior Court, 215 Cal. App. 2d 318 (1963).
Requests for admissions are not limited to matters within personal knowledge of the responding party, and a responding party has a duty to make a reasonable investigation of the facts before answering items which do not fall within his personal knowledge. It is not enough to fail to investigate and then deny for lack of information in reliance on the lack of investigation. Wimberly v. Derby Cycle Corp., 56 Cal. App. 4th 618 (1997).
Each answer in a response must be as complete and straightforward as the information reasonably available to the responding party permits. The responding party must admit or deny the request, or portions, true, or admit with qualifications, or specify any matter as to which the responding party lacks sufficient information or knowledge. If a responding party gives lack of information or knowledge as a reason for a failure to admit all or part of a request for admission, the response must state that a reasonable inquiry concerning the matter in the particular request has been made, and that the information known or readily obtainable is insufficient to enable that party to admit the matter. CCP Section 2033.220.
Chodos v. Superior Court, 215 Cal. App. 2d 318 (1963) held that a party to an action may not necessarily avoid responding to a request for admission on the ground that the request calls for an expert opinion and the party does not know the answer. "[S]ince requests for admissions are not limited to matters within personal knowledge of the responding party, that party has a duty to make a reasonable investigation of the facts before answering items which do not fall within his personal knowledge." Smith v. Circle P Ranch Co., 87 Cal. App. 3d 267 (1978).
When a request to admit is denied, if the propounding party proves the truth of those facts at trial, he or she may seek an award of the reasonable costs and attorney fees incurred in proving those facts. CCP Section 2033.420(a). Sanctions "shall" be awarded unless the court finds any of the following: (1) an objection to the request was sustained or a response to it was waived; (2) the admission sought was of no substantial importance; (3) the party failing to make the admission had reasonable grounds to believe that that the party would prevail on the matter; or (4) there was some other good reason for the failure to admit. CCP Section 2033.420(b); Laabs v. City of Victorville, 163 Cal. App. 4th 1242 (2008).