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Our tables rating individual firms will be more valuable to you if you know how the data were gathered and how they should be interpreted.
Customer survey scores reported on our tables are from our surveys of Consumer Reports and CHECKBOOK subscribers, conducted via mail and the Internet.
Since many firms were rated by rather small numbers of raters, small differences between two firms in the percentage of raters who gave a particular rating (say, "superior") should be ignored. The table below gives a rough guide to minimum differences you should look for in deciding on one firm over another.
When using these survey data, remember that the questions are to some degree subjective and that the differences among firms might be explained by differences in the personalities, backgrounds, critical standards, and other characteristics of the raters or by biases these raters might have.
Our ratings tables show the number of complaints filed against individual firms with the government offices of consumer affairs in Alexandria; in Arlington, Fairfax, Howard, and Montgomery counties; at the Consumer Protection Division of the Maryland Attorney General's Office; and at the Virginia Office of Consumer Affairs. These complaint counts are from a two-year period. Since the Complaint Division of the District of Columbia's Department of Consumer and Regulatory Affairs is closed, we were unable to count complaints there.
The ratings tables also show counts of complaints filed with the Better Business Bureau of Metropolitan Washington, DC (BBB), during a three-year period.
On the ratings tables we calculate complaint rates, where we are able, by dividing the number of complaints by the best measure we can devise of each firm's business volume and exposure to complaints.
There are limitations to the complaint data. One problem is that some complaints may be unjustified, simply filed by cranks. Another problem is that, in some cases, we didn't have a measure of business volume and therefore couldn't control for differences in firms' exposure to complaints.
We always recommend that you look for substantial differences in complaint counts and rates. We also advise giving little weight to complaint counts if the total count against a firm is less than three or four.
To gather much of the other information on our tables, we surveyed the firms. In general, our researchers surveyed firms by phone (sometimes without revealing their affiliation with CHECKBOOK), but in some cases data were collected by mail or from firms' websites, or phone responses were confirmed by mail follow-up.
To compute our price index scores, we calculated an average price for each job or item for all the firms that quoted on that job or item. Next we compared each firm's price to the average. One firm might come in at 120 percent of the multifirm average for a particular job, and another firm might come in at 90 percent. We took each firm's percentage score on each job or item, standardized it, and assigned a weight to each job or item, based on our judgment. We then averaged the standardized, weighted percentage scores to find how the firm compared to other firms overall. Finally, we multiplied this overall percentage score by a flat dollar amount, say, $100.
The price index score, then, is intended to indicate the relative prices we found for the firms, adjusted to the base of this flat dollar amount. These index scores are imperfect for various reasons: for instance, the jobs or items checked may not be representative; the weighting of various jobs or items in the index may not accurately reflect typical expenditure patterns; and the number of jobs or items is small.
All of the data must be interpreted in view of timeliness. Our customer survey data are from surveys conducted from April 2000 to June 2008. Survey respondents were asked to report on experiences in the preceding year. Our data on complaints for the government offices of consumer affairs are for a two-year period dating back from December 31, 2004. For the BBB, the data are for a three-year period dating back from a date from May to June 2005. Our price data were collected from June to September 2005.
For the most part, our tables include firms for which we collected 10 or more ratings on our customer survey during the customer survey period mentioned above, but we do not report data for periods prior to firms' changes of name and ownership. As a result, some large firms are not listed at all. If only name or ownership changed, we do report the data. Changes subsequent to the dates listed above may not be taken into account.
We give checkmarks to firms that score highest on a scoring system that we devise for each service field. Our scoring systems weight the various data in our tables and text based on our subjective judgment of their importance. Since the scores are based entirely on information presented, you can apply your own subjective judgments, and decide whether you prefer firms we have not given checkmarks. Where we do not have important data on a firm, we cannot give our checkmark.
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