The 10 Worst Automobile Brands in 2005
by James Bleeker
This page provides two rankings of the 10 worst brands of automobiles
sold 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 brands 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 brands is based on each brand's frequency of trouble-prone models. This ranking provides a measure of how unsuccessfully each brand's models 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.
Auto Brand Quality by Frequency of Trouble-Prone
Models: The Bottom 10 of 2005
To form a brand-quality measure from the 2005 list of Used Cars To Avoid, 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.
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 2005 Used-Cars-To-Avoid 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
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 brand and is achieved only when a brand has no entry on the Used-Cars-To-Avoid list.
The 10 worst car brands by the foregoing computations, together with their quality ratings, are given in the
first bar graph below. Only those brands with at least 5 overall CR reliability ratings are included.
Auto Brand Quality by the Average of Overall Reliability Ratings:
The Bottom 10 of 2005
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 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 10 worst car brands by this set of computations, together with their quality ratings, are given in the
second bar graph below. Only those brands with at least 5 overall CR reliability ratings are included.
The Bar Graphs of the Bottom 10
In both of the graphs that follow, the order of the car brands is with the worst on top.
Summary and Analysis
By frequency of trouble-prone models (first graph), the brands of General Motors Corporation
and the Chrysler Group account for 5 of the 10 worst brands
in 2005. GM brands on the 10-worst list are GMC, Oldsmobile (off-loaded in
2004), and Cadillac; Chrysler Group brands on the list are
Plymouth (off-loaded in 2001), and Dodge.
Also contributing to the trouble-prone list are Volkswagen's Audi and
Volkswagen brands, Jaguar, Mercedes-Benz, and Volvo.
Two brands that have taken quite a plunge in quality by
frequency of trouble-prone models are Volvo and Mercedes-Benz.
Both were within the Top 10 in 1995.
Two brands that were in the Bottom 10 in 1995 but were not in
2005 are Ford's Ford and Mercury brands. This provides further
evidence that Ford quality has been taking an upward path, as GM and
Chrysler quality has wondered about at or near the bottom end.
By overall unreliability (second graph), GM and the
Chrysler Group account for 5 of the ten worst brands in 2005; GM's are
GMC, Cadillac, and Pontiac (off-loaded in 2009), and Chrysler's are
Plymouth (off-loaded in 2001) and Dodge.
Also on the 10-worst list of 2005 by unreliability are Volkswagen's Audi
and Volkswagen brands, Jaguar, Mercedes-Benz, and Isuzu. Gone are Ford's
Ford and Mercury brands, both among the Bottom 10 in 1995.
There are 8 brands common to both worst-10 lists; they are:
2 Chrysler brands - Dodge and
2 General Motors brands - GMC and Cadillac
2 Volkswagen brands - Audi and Volkswagen
To view the 10 Best brand of 2005, click
To view the graphs showing the 2005 ratings and rankings of all brands, 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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