People called me crazy for claiming this as an innovation. As cars and trucks became more readily available and more "used", people began to trade them in. There was no guide for what a car would be worth after someone else owned it and if the car was being resold. NADA also known as the National, Automotive, Dealers, Association, gave a structured and accurate guide to pricing. It provided wholesale values, auction values, retail values and soon became available to not just dealers but consumers as well. The guide would provide values based on region, depreciation and would at a median line to pricing vehicles.