2005 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 1997 to 2004. 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
2005 issue of Consumer Reports. The two sections providing the necessary statistics are CR's Used-Cars-To-Avoid 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.
2005 Auto Manufacturer Quality by Infrequency of Trouble-Prone Models
To form a car-manufacturer quality measure from the 2005 list of Some Used Cars To Avoid, the first step is to count each manufacturer's entries on the list. Each model year of each model is treated as a separate entry.
Next, as the number of automobile models sold by a car manufacturer varies greatly from maker to maker, it is necessary to take account of the fact that a manufacturer 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 of a manufacturer, as well as a variability in model data sufficiency, the number of a manufacturer's entries in CR's
2005 Used-Cars-To-Avoid list is divided by the total number of overall reliability ratings for the manufacturer found in the reliability charts of the same issue of Consumer Reports. The overall reliability ratings are found in the
Reliability-Verdict row of the 2005 reliability charts.
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 car manufacturer and is achieved only when a manufacturer has no entry on the Used-Cars-To-Avoid list.
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.
2005 Auto Manufacturer Quality by the Average of Overall Reliability Ratings
To compute car-maker 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. Then an average is taken over all of the brand's model years and models offering an overall reliability rating. CR's
2005 overall reliability ratings are found in the Reliability-Verdict row of its reliability charts
and are limited to three grades - Better Than Average, Average, and Worse
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 2005
In both of the graphs that follow, the order of the car manufacturers is from best to worst.
Summary and Analysis
In 2005, the Top 3 auto manufacturers
by infrequency of trouble-prone
models were, in descending order (best first), Fuji Heavy Industries
Ltd., Suzuki Motor Corporation, and Toyota Motor Corporation.
The Bottom 3 auto manufacturers
by frequency of trouble-prone models were, in
ascending order (worst first), Volkswagen AG, Jaguar, and Daimler AG
In 2005, the Top 3 auto manufacturers
by overall reliability were, in descending
order, Toyota Motor Corporation, Honda Motor Company, and Fuji Heavy
The Bottom 3
by overall reliability, in ascending order
(worst first), were Jaguar, Volkswagen AG, and Daimler AG
Two car manufacturers are common to the Top 3 of both quality rankings:
Fuji Heavy Industries (maker of the Subaru)
Three car manufacturers are common to the Bottom 3 of both quality rankings:
Daimler AG (maker of Mercedes-Benz)
In 2005, neither General Motors nor Chrysler made the worst-three list by
either quality measure.
To view the graphs showing the 2005 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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