Annual & Quarterly Services

Benchmarking to the 2002 Economic Census

We adjusted the estimates for 1998 through 2004 using results of the 2002 Economic Census. Before adjusting, we made historical corrections to data from 1998 through 2003. Then, we adjusted by multiplying the sample-based total estimates for each detailed industry--generally defined by 6-digit NAICS codes--by a ratio of revenue totals for reference year 2002. The numerator and denominator of the ratio were as follows:

• The numerator was the 2002 Economic Census revenue total of the industry on a 1997 NAICS basis;
• The denominator was the 2002 SAS sample revenue total of the industry.

We computed separate adjustment ratios for each detailed industry. We applied the same adjustment ratio to each data item of interest (e.g., total revenue, expenses).

We calculated total estimates at broad industry levels (i.e., 2-, 3-, 4-, and 5-digit NAICS levels) by summing the census-adjusted totals for the appropriate detailed industries comprising the aggregate.

Year-to-year change estimates were computed using the appropriate census-adjusted totals for the industry and time period.

For Truck Transportation (NAICS 484), we did not adjust estimates of the following:

• Inventories of Revenue Generating Equipment by Type of Carrier;
• Number of Truck Miles.

Instead, we produced estimates for these data items directly from the sample.