§ 2030.410.Trial or hearing in which respondent is a party

Answers given under oath during discovery do not just sit in a file until trial; this section lets them come into evidence directly against the party who gave them. Any party other than the responding party, whether that is the party who propounded the interrogatory or another party to the same action, may use an answer, or any part of one, at trial or at any other hearing, but only against the party who gave that answer, and only so far as the rules of evidence otherwise allow it in. In practice this functions much like using a party's own prior statement against that party, a direct and often powerful way to hold a litigant to its own sworn words.

The second sentence forecloses the objection responding parties most often raise against this use: that the answer should not come in because the responding party is available to testify at the hearing, has already testified, or will testify later. None of that matters. The propounding party, or any other party, does not have to call the responding party to the stand first, or wait for that party's live testimony, before introducing a prior interrogatory answer; the two are independent, and the availability or occurrence of live testimony is not a ground for keeping the sworn answer out.