N.H. R. Evid. 407
When measures are taken that would have made an earlier injury or harm less likely to occur, evidence of the subsequent measures is not admissible to prove:
. negligence;
. culpable conduct;
. a defect in a product or its design; or
. a need for a warning or instruction.
But the court may admit this evidence for another purpose, such as impeachment or - if disputed - proving ownership, control, or the feasibility of precautionary measures.
N.H. R. Evid. 407
2016 NHRE Update Committee Note
The amendment made by supreme court order dated April 20, 2017, effective July 1, 2017, made stylistic changes to the rule.
The 2016 provides that the evidence of subsequent remedial measures may not be used to prove, "a defect in a product or its design," or that a warning or instruction should have accompanied a product. The language of the amended rule mirrors Federal Rule of Evidence 407. For additional guidance regarding the substantive changes to the rule see the notes following Federal Rules of Evidence 407 (Notes of Advisory Committee on 1997 amendments).