Collateral source evidence shows payments from sources independent of the defendant, traditionally inadmissible.

Evidence of liability insurance is inadmissible to prove negligence but admissible for other purposes.

Offers to compromise are inadmissible to prove liability or damages, encouraging settlement discussions.

Payment of medical expenses is inadmissible to prove liability, encouraging humanitarian assistance.

Subsequent remedial measures are post-incident fixes that are inadmissible to prove negligence or defect, though admissible for other limited purposes.