How We Gather (and How to Interpret) Our Data

            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.

Price Index Scores

            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, and assigned a weight to each job or item, based on our judgment. We then averaged the 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.  

Timeliness of the Data

            All of the data must be interpreted in view of timeliness. Our price data were collected from November 2003 to February 2004.  

Top Ratings

            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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