The loss, destruction, alteration, or failure to preserve evidence that could matter in a legal claim.

"Evidence" can mean physical items, photos, video, electronic data, maintenance logs, medical records, phone data, or damaged equipment. "Preserve" means keeping that material in the condition it was in when a dispute became likely, not just after a lawsuit is filed. "Could matter" is broad: the evidence does not have to prove the whole case by itself. If it might help show fault, injury, timing, notice, or damages, it may need to be kept. Spoliation can be intentional, like deleting footage, or careless, like throwing away a machine part after an accident.

In practice, spoliation can change the direction of an injury case. If a business loses cleaning records after a fall, or a trucking company erases onboard data after a highway crash on SR-1, the missing material may make it harder to prove what happened. A court may respond with sanctions, limits on defenses, or an adverse inference allowing a jury to assume the missing evidence would have hurt the party who failed to preserve it.

In Delaware, courts address spoliation through case law and court rules, including Delaware Superior Court Civil Rule 37 on discovery sanctions. Early preservation letters often matter because they put the other side on notice to keep relevant evidence.