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News, Analysis and EditorialAre the J.D. Power Quality Survey Results Worth Less
Than the Recyclable Paper They Are Printed On?
Auto on Info June 2005
Are the J.D. Power Quality Survey Results Worth Less Than the Recyclable Paper They Are Printed On?
By James Bleeker
To help answer the question, we'll do a little math. We begin with the following table.
Survey Results by Motor Vehicle Line Motor Vehicle Line Average Number of Serious Problems for Model Year 2004, per Consumer Reports Survey Average Number of Complaints for Model Year 2004, per J.D. Power's Initial Quality Survey Subaru 8 138 Honda 9 112 Acura 10 116 Toyota 10 105 Hyundai 11 110 Infiniti 11 109 Lexus 11 81 Audi 12 106 Mini 13 130 Ford 15 127 Pontiac 15 129 Cadillac 16 104 Chevrolet 16 127 Chrysler 16 121 GMC 16 113 Jeep 16 120 Mazda 16 149 Saab 16 136 Dodge 17 130 Mercury 17 120 Volvo 17 140 Buick 18 100 Nissan 19 120 Saturn 19 136 BMW 21 95 Volkswagen 23 147 Mercedes-Benz 25 104 Lincoln 26 113 The first column is from "Consumer Reports' Reliability Rankings," March 7, 2005, by the Associated Press. The second column is from "Toyota and GM Lead in Quality Survey," May 19, 2005, the Detroit News. Only models offering both a CR serious problem average and a J.D. Power complaint average appear in the table.
(Advisory: Site manager views the performance of a model or line within the first 90 days or 6 months as no basis for selecting a vehicle to purchase, and barely a factor among the complex of reasons for selecting a vehicle.)
Next, we put a minus sign in front of the above numbers (take the additive inverse of the values), insert them into Microsoft's Excel, and let the software compute the corresponding percentranks. This gives us the following table.
Survey Results by Motor Vehicle Line Motor Vehicle Line Percentranks of Average Number of Serious Problems for Model Year 2004, per Consumer Reports Survey Percentranks of Average Number of Complaints for Model Year 2004, per J.D. Power's Initial Quality Survey Subaru 1.00 .11 Honda .96 .67 Acura .89 .56 Toyota .89 .81 Hyundai .78 .70 Infiniti .78 .74 Lexus .78 1.00 Audi .74 .78 Mini .70 .22 Ford .63 .33 Pontiac .63 .30 Cadillac .37 .85 Chevrolet .37 .33 Chrysler .37 .41 GMC .37 .59 Jeep .37 .44 Mazda .37 0.00 Saab .37 .15 Dodge .26 .22 Mercury .26 .44 Volvo .26 .07 Buick .22 .93 Nissan .15 .44 Saturn .15 .15 BMW .11 .96 Volkswagen .07 .04 Mercedes-Benz .04 .85 Lincoln 0.00 .59 Next, we plot J.D. Power's percentranks versus CR's percentranks and insert a linear regression. We have:
From the graph, it may be seen that the regression line is nearly horizontal, meaning that there is nearly no relationship between the two. (A diagonal line going from the bottom left corner to the top right corner and with plotted points nearly coincident with the line would indicate a very strong correspondence.)
So, why don't J.D. Power's initial "quality" 90-day early ownership survey results more closely match Consumer Reports' early ownership serious problem survey results? There are likely three primary factors for J.D. Power's poor match.
1. J.D. Power's early ownership survey solicits complaints by owners and makes no distinction between more serious complaints and complaints of a less serious or trivial nature.
2. A typical GM owner may be quite content with the fact that the vehicle runs, while, say, a Toyota owner may expect something close to perfection in operation, appearance, and performance. Consequently, the J.D. Power survey may greatly understate "comparable" complaints with GM Products (possibly, by an order of magnitude, but this is just a guess). Expressed simply, the J.D. Power early survey results likely permit little or no comparison between products of differing manufacturers; its usefulness likely rests rather exclusively in alerting consumers to greater problems when the same model or line generates a much larger number of complaints from one year to the next.
3. Very early ownership surveys are likely of very little value, as even General Motors vehicles likely hold together well enough in the first 90 to 180 days to keep GM customers content.
The third factor raises the question: Do J.D. Power's results improve, relative to Consumer Reports data-driven statistics, when its complaint survey covers the first three years rather than the first 90 days? Some, but not much. For example, by its 2003 3-year ownership survey results, the 2000 Buick line, with a 2-to-4 year Reliability Percentrank average of .57 and a Reliability Grade of F, placed number 3 in J.D. Power results, and the 2000 Cadillac line, with a 2-to-4 year Reliability Percentrank average of .10 and a Reliability Grade of F, placed number 7, while the 2000 Toyota line, with a 2-to-4 year Reliability Percentrank average of .91 and a Reliability Grade of A-, placed number 6, and the 2000 Honda line, with a 2-to-4 year Reliability Percentrank average of .77 and a Reliability Grade of C, placed number 9.
Plotting the J.D. Power 3-year complaint percentranks for model year 2000 against the percentranks of Auto on Info 2-to-4 year Reliability Scores for model year 2000 and inserting the linear regression, we have:
Here we see more of a diagonal, but plotted points are far from linearly coincident.
Of course, there is the possibility that J.D. Power results are completely drylabbed. Site manager proposes an independent audit, together with a detailed description of methodology to see whether anyone else can duplicate the results.
Source for Consumer Reports serious problem averages for model year 2004: "Consumer Reports' Reliability Rankings," March 7, 2005, the Associated Press, available at Yahoo! News
Source for J.D. Power 90-day complaint averages for model year 2004: "Toyota and GM Lead in Quality Survey," May 19, 2005, Christine Tierney, Detroit News, at http://www.detnews.com/2005/autosinsider/0505/19/C01-186788.htm
Source for J.D. Power 3-year complaint averages for model year 2000: "A Car You Can Depend On?" July 9, 2003, Wall Street Journal, p. D5
Source for Auto on Info 2-to-4 year Reliability Scores for model year 2000: Table I-MVRS
Source for Auto on Info 2-to-4 year Reliability Percentranks for model year 2000: Table I-MVRP
Source for Auto on Info 2-to-4 year Reliability Grades for model year 2000: Table I-MVRGH
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