What are the factors in weighting whether to disclose substantive evidence vs. using it for impeachment at trial?

On one hand, the jury gets to see substantive evidence but the other side is alerted to it before trial and can prepare. On the other hand, with impeachment evidence, the other side can be surprised, but the jury does not get to see it.

Which tends to be more effective?

1 Answer 1


What are the factors in weighting whether to disclose substantive evidence vs. using it for impeachment at trial?

In an adversarial system (such as that in the jurisdictions in the U.S.) the surprise factor is disallowed on trial.

I am not knowledgeable on the procedural exceptions, but generally speaking the documentary evidence (including deposition transcripts) has to be filed during the discovery stage of proceedings. A discovery deadline is set up during case scheduling, and extensions of that deadline have to be requested via motion.

There is the slightly related concept of sequestration of witnesses whereby inconsistencies may serve to impeach a witness's testimony, but that is different than withholding from the jury any pre-existing evidence that a plaintiff would like to be considered on trial (whether for impeachment or otherwise).

Also, it is in the injured party's best interest that the jury get to see the evidence rather than have it merely rely on a witness's reaction of surprise. The wrongdoer's lawyer will try to confuse the jury and thus outweigh the jury's perception of a "surprised witness", but that attempt is likelier to fail if the jury has the evidence with which to compare the witness's testimony at trial.

  • Could you perhaps flesh out the last sentence in your answer? I'm not sure I understand it. What do you mean by "easier to override, or maybe to reverse on appeal"? Thank you.
    – Gill Hamel
    Commented Oct 4, 2019 at 18:49
  • @GillHamel I edited the last paragraph. Let me know if that is clearer. Commented Oct 4, 2019 at 19:36
  • It is, thank you. I read the order on your case. It looks like according to the court your case fell on the "actual malice" sword. There is some argument and concern about what constitutes sufficient circumstantial evidence to pass SJ on this issue. You will like the following panel discussion a lot and I think you will be nodding all the way through: youtube.com/watch?v=Q-yjN_RXZPc
    – Gill Hamel
    Commented Oct 4, 2019 at 20:36
  • Also see Durando v. Nutley Sun, 37 A. 3d 449 - NJ: Supreme Court 2012 for another "def. friendly" decision on this issue.
    – Gill Hamel
    Commented Oct 4, 2019 at 20:36

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