2010 Auto Brand Quality Ratings and Rankings
by James Bleeker
This page provides two rankings of the brands of automobiles sold 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 brands 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 brands is based on each brand's infrequency of trouble-prone models. This ranking provides a measure of how well each brand's models successfully avoided the bottom end of the model-quality spectrum.
The second ranking of the car brands is based on the average of the overall reliability ratings of each brand's models. The second ranking provides a measure of how well a brand's models performed over the entire model-quality spectrum.
2010 Auto Brand 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 car brands by the foregoing computations, together with their quality ratings,
is given in the first bar graph below. Only those brands with at least 5 overall CR reliability ratings are included.
2010 Auto Brand 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 brands by this set of computations, together with their quality ratings,
is given in the second bar graph below. Only those brands with at least 5 overall CR reliability ratings are included.
The Bar Graphs of 2010 Brand Quality
In both of the graphs that follow, the order of the car brands is with the
best on top.
When two or more brands have no entry in CR's list of
Cars, the brands are listed in descending order of
number of overall reliability ratings (a brand with a greater
number of overall reliability ratings appears above a brand with
fewer ratings), as those brands with a greater number of ratings
would have a greater opportunity for a trouble-prone model year
to be found.
Summary and Analysis
Some important points given by the above graphs are:
1. In 2010, two of Ford Motor
Company's three North American brands were in the top half
by infrequency of trouble-prone models and all three were in
the top half by overall reliability.
2. In 2010, all three of the Chrysler Group's
remaining brands - Chrysler, Dodge, and Jeep - were in the
bottom half by both quality measures.
3. In 2010, all of General Motors'
North American brands were in the bottom half by overall
reliability; all but the Buick brand were in the bottom half by
infrequency of trouble-prone models.
4. In 2010, all three of Toyota Motor
Corporation's brands, Scion, Toyota, and Lexus, both of Honda Motor Company's
brands, Acura and Honda, and Nissan Motor Company's Infiniti
Top 6 by both measures of quality.
5. The Hyundai brand, which placed worst of
all brands by both quality measures in 1995, outranked all North
American and European brands in 2010 by both quality measures.
Subaru and Mazda similarly outranked all North American and
European brands in 2010.
To view the graphs showing the 2010 ratings and rankings of the car
manufacturers, click Go.
For a Google Knol that summarizes the changes in auto-brand and auto-manufacturer ranking by these quality measures from 1990 to 2010, click
AutoOnInfo.net: The auto-quality website with the
Open Directory Cool Site Award.