To compute the reliability-durability grade point average of the MY 1987 cars, Consumer Reports' reliability ratings for the age range 4-to-5 years are used. For the R-D GPAs for model year 1975 to 1986, Consumer Reports' reliability ratings for the age ranges 4-to-5 years and 5-to-6 years are used. The reason for the difference is that CR did not provide an overall reliability rating (a component in the computation of the Reliability-Durability GPA) for much of the 1990s and the first half of the 2000s.

CR's ratings are converted to numerical values following the standard academic pattern: a grade point of 4.0 (an A) is accorded a rating of Much Better Than Average, a 3.0 (a B) is accorded a rating of Better Than Average, a 2.0 (a C) is accorded a rating of Average, a 1.0 (a D) is accorded a rating of Below Average, and a 0 (an F) is accorded a rating of Much Below Average.

Then, the grade point of CR's overall reliability rating is weighted 2/3 and the average of the grade points of the category ratings is weighted 1/3.

Finally, a car maker's Reliability-Durability GPA is computed by taking the average of the Reliability-Durability GPAs of its models.

Best and Worst Car Manufacturers of Each Model Year

Worst Car Brands by CR's List of Used Cars to Avoid:  1985  1986  1987  1988  1989  1990  1991  1992  1993  1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006

Best Car Makers by CR's List of Used Cars to Avoid: 1985  1986  1987  1988  1989  1990  1991  1992  1993  1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006

Worst Car Makers by CR's List of Used Cars to Avoid:  1985  1986  1987  1988  1989  1990  1991  1992  1993  1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006