This article provides two methods for selecting the 7 best car brands sold in North America from late 2004 to 2009. The statistics used in the computations for selecting the seven best vehicle brands are those found within the April 2010 issue of Consumer Reports, likely the most respected and followed source of automobile quality information in North America. The two sections used for ranking brand quality are Consumer Reports' list of trouble-prone cars 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 Top 7 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 Top 7 car brands is based on the average of the overall reliability ratings of each brand's models. The second ranking provides a measure of well a brand's models performed over the entire model-quality spectrum.
In each of its April issues, Consumer Reports has listed the most trouble-prone models by model year since 1976. 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 next 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 variability in model data sufficiency, the number of a brand's entries in CR's 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.
