Title insurance differs in several respects from other types of insurance. Where most insurance is a contract where the insurer indemnifies or guarantees another party against a possible specific type of loss (such as an accident or death) at a future date, title insurance generally insures against losses caused by title problems that have their source in past events. This often results in the curing of title defects or the elimination of adverse interests from the title before a transaction takes place. Title insurance companies attempt to achieve this by searching public records to develop and document the chain of title and to detect known claims against or defects in the title to the subject property. If liens or encumbrances are found, the insurer may require that steps be taken to eliminate them (for example, obtaining a release of an old mortgage or deed of trust that has been paid off, or requiring the payoff of such lien) before issuing the title policy. In the alternative, it may “except” those items not eliminated from coverage. Title plants are required to be maintained to index the public records geographically, with the goal of increasing searching efficiency and reducing claims.