This rule of evidence not only affects trial and trial planning, but was specifically established as a matter of social policy, to encourage timely remedial measures after events in which persons or property are injured, and thus decrease the risk of additional injuries. Unrestricted admissibility of remedial measures would discourage taking such measures until all opportunities for litigation were exhausted, a matter of years. The most disadvantageous version of the rule (in this case the state's) will influence a prospective defendant's conduct. Therefore, the intended social benefit of the Federal rule cannot be realized unless the State rule is made to conform to it.