2010 Automobile Manufacturer Quality Ratings and Rankings
by James Bleeker
This page provides two rankings of the manufacturers of automobiles with more significant sales in North America
from model year 2004 to 2009. Each ranking employs a different method of computation.
The statistics used in the computations for rating and ranking the car makers are those found within the April
2010 issue of Consumer Reports. The two sections providing the necessary statistics are CR's Worst-Cars list and its reliability charts. Reliability is defined by the magazine as the infrequency of serious problems, which it measures annually by a subscriber survey.
The first ranking of the car makers is based on each manufacturer's infrequency of trouble-prone models. This ranking provides a measure of how well each manufacturer's models successfully avoided the bottom end of the model-quality spectrum.
The second ranking of the car makers is based on the average of the overall reliability ratings of each manufacturer's models. The second ranking provides a measure of how well a manufacturer's models performed over the entire model-quality spectrum.
2010 Auto Manufacturer Quality by Infrequency of Trouble-Prone Models
To form a brand-quality measure from the 2010 list of Worst Cars, the first step is to count each brand's entries on the list. Each model year of each model is treated as a separate entry. For the 2010 computations, only entries from the 6 most-recent model years are counted, for the reason explained in the following paragraph.
Next, as the number of automobile models sold under a brand name varies greatly from brand to brand, it is necessary to take account of the fact that a brand with more models has a greater opportunity to have more model years of low quality. To compensate for a possibly inflated, or deflated, frequency of trouble-prone model years within a brand, as well as a variability in model data sufficiency, the number of a brand's entries in CR's
2010 Worst-Cars list is divided by the total number of overall reliability ratings for the brand found in the reliability charts of the same issue of Consumer Reports. The overall reliability ratings are found in the
Used-Car-Verdicts row of the 2010 reliability charts. As the 2010 reliability charts are limited to the 6 most-recent model years, the count of a brand's entries on the Worst-Cars list is limited to the 6 most-recent model years as well.
By the method of computation, this quality measure begins with 0 and may run to a value some greater than 1. The value of 0 is the highest quality rating attainable by a brand and is achieved only when a brand has no entry on the
The quality ranking of the automobile manufacturers by the foregoing computations, together with their quality ratings, are given in the
first bar graph below. Only those manufacturers with at least 5 overall CR reliability ratings are included.
2010 Auto Manufacturer Quality by the Average of Overall Reliability Ratings
To compute brand-quality ratings and assemble a brand-quality ranking using Consumer Reports' overall reliability ratings, a number is associated with each rating. A +1.0 is ascribed to a rating of Much Better Than Average, a +0.5 to a rating of Better Than Average, a 0 to a rating of Average, a -0.5 to a rating of Worse Than Average, and a -1.0 to a rating of Much Worse Than Average. Then an average is taken over all of the brand's model years and models offering an overall reliability rating. CR's
2010 overall reliability ratings are found in the Used-Car-Verdicts 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 ranking of the car manufacturers by this set of computations, together with their quality ratings, are given in the
second bar graph below. Only those manufacturers with at least 5 overall CR reliability ratings are included.
The Bar Graphs of Auto Manufacturer Quality in 2010
In both of the graphs that follow, the order of the car manufacturers is from best to worst.
Summary and Analysis
In 2010, the Top 3 auto manufacturers
by infrequency of trouble-prone
models were, in descending order (best first),
Honda Motor Company, Toyota Motor
Corporation, and Hyundai Motor Company. All three had a perfect score by
this quality measure.
The Bottom 3 auto manufacturers
by frequency of trouble-prone models were, in
ascending order (worst first), General Motors Corporation, BMW AG, and
Chrysler Group LLC (current name).
In 2010, the Top 3 auto manufacturers
by overall reliability were, in descending
order, Toyota Motor Corporation, Honda Motor Company, and Fuji Heavy
Industries Ltd., the same as in 2005.
The Bottom 3
by overall reliability, in ascending order
(worst first), were Chrysler Group LLC (current name), Saab, and
General Motors Corporation.
Two car manufacturers are common to the Top 3 of both quality rankings:
Two car manufacturers are common to the Bottom 3 of both quality rankings:
In 2010, General Motors and Chrysler made the worst-three list by
both quality measures.
To view the graphs showing the 2010 ratings and rankings of the brands of automobiles, click
For a Google Knol that summarizes the changes in auto-brand and auto-manufacturer ranking by these quality measures from 1990 to 2010, click
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