File:2005 Car Maker Quality Ratings by Overall Reliability.png

English: Bar Chart of the 2005 Car Manufacturer Quality Ratings by Overall Reliability

This rating of the car manufacturers is an average of the overall reliability ratings of the manufacturer's models. It provides a measure of how well a company's models performed over the entire model-quality spectrum.

The formation of this measure of quality is based on the reliability charts of Consumer Reports.

To compute manufacturer-quality ratings and assemble a manufacturer-quality ranking using Consumer Reports' overall reliability ratings, a number is associated with each rating. A +1.0 is ascribed to a rating of Better Than Average, a 0 to a rating of Average, and a -1.0 to a rating of Worse Than Average. (In 2005, Consumer Reports used 3 ratings rather than its usual 5 ratings.) Then an average is taken over all of the company's model years and models offering an overall reliability rating in the April 2005 issue of Consumer Reports. CR's 2005 overall reliability ratings are found in the Reliability-Verdict row of its reliability charts.

For this measure of quality, the range is from -1.0 (the worst possible) to +1.0 (the best possible).

The quality ratings of the car manufacturers by this set of computations are given in the bar graph above. Only those manufacturers with at least 5 overall CR reliability ratings are included.

For the 1975, 1980, 1985, 1990, 1995, 2000, 2005, and 2005 charts providing the automobile-manufacturer quality ratings and rankings by overall reliability and infrequency of trouble-prone models, Saab, Volvo, and Jaguar are treated as independent companies.

For a Google Knol that summarizes the changes in car brand and manufacturer ranking by this quality measure from 1990 to 2010, visit http://knol.google.com/k/james-bleeker/automobile-quality-by-car-brand-and/3o3u27f0whd6k/2?hd=ns# .