Section 3.24 Duty to Supplement Answers

• Library: Discovery 2015

Caselaw in Missouri establishes a duty to supplement responses to interrogatories. Laws v. City of Wellston, 435 S.W.2d 370, 375 (Mo. 1968). Rule 56.01(e) describes the nature of that duty.

A party must “seasonably” supplement prior responses if the party learns that the response is in some material respect incomplete or incorrect and if the addition or corrective information has not otherwise been made known to the other parties during the discovery process or in writing. For example, in Birdsong v. Christians, 50 S.W.3d 420, 422 (Mo. App. S.D. 2001), the court noted that a duty to seasonably supplement attaches if a party obtains information upon which the party knows that the initial response was incorrect or unreliable when made or that the initial response, though correct when made, is no longer true. InBirdsong, the court stated that: “The application of the rule should not require the disclosure of every bit of information discovered after the answers are served, but should require that any information which is of a substantial nature and which will render the answers theretofore served untruthful, unreliable, or incomplete must be disclosed.” Birdsong, 50 S.W.3d at 422.

“Seasonably” has been defined as within a “reasonable time.” SeeState ex rel. Mo. Highway & Transp. Comm’n v. Pully, 737 S.W.2d 241, 244 (Mo. App. W.D. 1987). The determination of whether a party provided a supplemental interrogatory response within a reasonable time is “made on a case-by-case basis, considering all the facts and circumstances.” Id. at 245.

The failure of a party to timely supplement answers to interrogatories that seek the identity and qualifications of any expert expected to testify at trial may result in exclusion of all or a portion of that expert’s testimony. State ex rel. Mo. Highway & Transp. Comm’n v. Vitt, 785 S.W.2d 708, 711–12 (Mo. App. E.D. 1990).

Unlike Federal Rule of Civil Procedure 26(e), which applies the requirement to all forms of discovery, Rule 56.01(e) limits the duty to supplement to answers to interrogatories, requests for production, and requests for admission. But while the Rule makes no express provision for an obligation to supplement deposition responses when a truthful answer later ceases to be correct, the Rules and the case authority considered as a whole suggest that this duty is implied as a component of the discovery process. Gassen v. Woy, 785 S.W.2d 601, 603–04 (Mo. App. W.D. 1990). It has been held that a witness whose...