The list is put together by the Highway Loss Data Institute, an arm of the Insurance Institute for Highway Safety. The HLDI derived its data from the insurance claims people filed for stolen vehicles.
By looking at claims per insured vehicle year, HLDI’s theft reports allow people to compare the relative risk of each vehicle. In contrast, other most-stolen-vehicle lists report raw numbers of thefts and are therefore dominated by the most common vehicles on the road.
HLDI’s whole-vehicle theft report differs from its standard theft report, which looks at all theft claims, including those for stolen vehicle parts or for items taken from a vehicle.
To isolate whole-vehicle claims, HLDI looked at the amounts paid for total losses under collision coverage, which is generally the residual value of the vehicle. If the payment associated with a theft claim is around the same as would be expected for a total loss under collision coverage for the same vehicle of the same age, it is considered to be a whole-vehicle theft claim.