Estimated Quarterly U.S. Retail E-commerce Sales:
4th Quarter 1999– 2nd Quarter 2004

(Estimates not adjusted for seasonal variation, holiday or trading-day differences, or price changes)

Billions of dollars

E-commerce retail sales data and frequently asked questions (FAQ’s) about e-commerce sales are available on the Census website at www.census.gov/mrts/www/mrts.html. For additional information about Census Bureau e-business measurement programs and plans visit www.census.gov/estats.

Table 1.Estimated Quarterly U.S. Retail Sales¹: Total and E-commerce

NA Not available. (r) Revised. (p) Preliminary.

¹Estimates exclude Food Services.

²E-commerce sales are sales of goods and services where an order is placed by the buyer or price and terms of sale are negotiated over an Internet, extranet, Electronic Data Interchange (EDI) network, electronic mail, or other online system. Payment may or may not be made online.

³Estimated measures of sampling variability (shown as percents) for 2nd quarter 2004 estimates -4.3; standard error (se) of e-commerce as a percent of total sales -0.1; se of quarter-to-quarter change in total sales -0.2; se of quarter-to-quarter change in e-commerce -1.2; se of current quarter to same-quarter-a-year-ago change in total sales -0.4; se of current quarter to same-quarter-a-year-ago change in e-commerce -1.8. Measures of sampling variability for estimates from prior quarters can be obtained by dividing the margin of error for the estimate as published in the Reliability of Estimates section of prior releases by 1.645.

Note: Estimates are not adjusted for seasonal variation, holiday or trading-day differences, or price changes. For information on confidentiality protection, sampling error, nonsampling error, sample design, and definitions, see http://www.census.gov/mrts/www/nrely.html.

Description of the Survey

Retail e-commerce sales are estimated from the same sample used for the Monthly Retail Trade Survey (MRTS) to estimate preliminary and final U.S. retail sales. Advance U.S. retail sales are estimated from a subsample of the MRTS sample that is not of adequate size to measure changes in retail e-commerce sales.

A stratified simple random sampling method is used to select approximately 11,000 retail firms whose sales are then weighted and benchmarked to represent the complete universe of over two million retail firms. The MRTS sample is probability based and represents all employer firms engaged in retail activities as defined by the North American Industry Classification System (NAICS). Coverage includes all retailers whether or not they are engaged in e-commerce. Online travel services, financial brokers and dealers, and ticket sales agencies are not classified as retail and are not included in either the total retail or retail e-commerce sales estimates. Nonemployers are represented in the estimates through benchmarking. E-commerce sales are included in the total monthly sales estimates.

The MRTS sample is updated on an ongoing basis to account for new retail employer businesses (including those selling via the Internet), business deaths, and other changes to the retail business universe. Research was conducted to ensure that retail firms selected in the MRTS sample and engaged in e-commerce are representative of the universe of e-commerce retailers.

Firms are asked each month to report e-commerce sales separately. For each month of the quarter, data for nonresponding sampling units are imputed from responding sampling units falling within the same kind of business and sales size category. Approximately 15 percent of the e-commerce sales estimate for second quarter 2004 was imputed. Imputed total retail sales data accounted for approximately 20 percent of the estimate of U.S. retail sales for the second quarter 2004.

For each month of the quarter, estimates are obtained by summing weighted sales (either reported or imputed). The monthly estimates are benchmarked to prior annual survey estimates. Estimates for the quarter are obtained by summing the monthly benchmarked estimates. For second quarter 2004, the estimate for June is a preliminary estimate. Therefore, the estimate is subject to revision. Individuals who use estimates in this report to create new estimates should cite the Census Bureau as the source of only the original estimates.

Reliability of Estimates

Because the estimates in this report are based on a sample survey, they may contain sampling error and nonsampling error.

Sampling error is the difference between the estimate and the result that would be obtained from a complete enumeration of the population conducted under the same survey conditions. This error occurs because only a subset of the entire population is measured in a sample survey. The margin of error, as used on page 1, gives a range about the estimate, which is a 90 percent confidence interval.

The margin of error for the change in U.S. retail e-commerce sales from the first quarter 2004 to the second quarter 2004 is approximately 0.9%, giving a range of 0% to 1.8%. Range estimates are computed based on the particular sample selected and canvassed. If we had repeated the process of drawing all possible samples and forming all corresponding range estimates, approximately 90 percent of these individual range estimates would have contained the quarter-to-quarter change in e-commerce sales computed from a complete enumeration of all retail firms on the sampling frame. Because the range above contains 0%, we cannot conclude at the 90 percent confidence level that retail e-commerce sales increased from the first quarter 2004 to the second quarter 2004. The Census Bureau recommends that individuals using estimates in this report incorporate this information into their analyses, as sampling error could affect the conclusions drawn from the estimates.

Nonsampling error encompasses all other factors that contribute to the total error of a sample survey estimate. This type of error can occur because of nonresponse, insufficient coverage of the universe of retail businesses with e-commerce sales, mistakes in the recording and coding of data, and other errors of collection, response, coverage, or processing. Although not directly measured, precautionary steps are taken to minimize the effects of nonsampling error.

The U.S. Census Bureau, pre-eminent collector and disseminator of timely, relevant, and quality data about the people and the economy of the United States, conducts a population and housing census every 10 years, an economic census every five years, and more than 100 demographic and economic surveys every year, all of them evolving from the first census in 1790.

•  Monthly Retail Trade Survey Main Page

Source: Retail Indicators Branch, U.S. Census Bureau
Last Revised: August 20, 2004