J.D. Power publishes ratings for used cars in the form of its annual Vehicle Dependability Study. The study surveys thousands of original owners of 3-year-old cars to find the quantity and nature of any problems they may have experienced with their vehicles.
All cars covered under the Vehicle Dependability Study receive a rating measured in problems per 100 vehicles, with lower numbers indicating fewer problems experienced by owners during the preceding 12 months. Cars covered in the 2015 study are from model year 2012. Prospective buyers seeking information on older used cars can check with older versions of the study.
For newer cars, J.D. Power also publishes its annual Initial Quality Study, documenting the number of problems new car owners have experienced during the first 90 days of ownership. While it does not measure true long-term reliability, this study can also be a good predictor of potential trouble-free ownership over time.