National Agricultural Statistics Overview
Data Sources and Estimation Procedures
Administrative Data Sources
Summary

The National Agricultural Statistics Service (NASS) administers the United States Department of Agri culture's program for collecting and publishing timely national and state agricultural statistics. In 1862, the first Commissioner of the newly formed Depart ment of Agriculture, Isaac Newton, established a goal to "collect, arrange, and publish statistical and other useful agricultural information." A year later, in July 1863, the Department's Division of Statistics issued the Nation's first official Crop Production report.

The structure of farming, ranching, and the agricul tural industry has changed dramatically during the succeeding 130 years. The need for accurate, timely, and objective statistical information about the Nation's agriculture has become even more impor tant as the country has moved from subsistence agriculture to a highly industrialized business that produces food and fiber for the world market.

The National Agricultural Statistics Service now publishes nearly 400 reports a year with official estimates covering over 120 crops and 45 livestock items. Each report is issued according to a pub lished annual calendar of release dates. Strict security procedures ensure that no one gains premature access to the information. In addition, NASS has a strong tradition of cooperation with other federal agencies, state departments of agricul ture, and universities to supplement the federal statistics program. The state-federal cooperative relationship, which began over 75 years ago, eliminates duplication and provides state input while maintaining consistency in surveys conducted across the U.S.

The official estimates prepared by NASS are based on data obtained from farm and ranch operators, as well as from agribusinesses such as grain elevators, shippers, processors, and commercial storage firms. Scientifically designed sampling methods are used to determine the operations to be included in each survey. Operators are interviewed by professionally trained interviewers, either in person or by tele phone. In some instances operators will receive a

questionnaire by mail with a postage-paid return
envelope. Anyone not returning the form is usually telephoned; however, survey response is voluntary. Very stringent laws and procedures protect the confidentiality of each operator's response.

NASS maintains extensive lists of farm and ranch operations along with identifiers that indicate size and type of operation. NASS also maintains com plete lists of grain storage facilities, commercial operations such as feedlots, cold storage facilities, and manufactured dairy processors. Nearly every report issued by NASS is based on survey sample data collected from farms or other agribusinesses selected from these lists.

NASS also maintains an area sampling frame. The area frame, which is essentially the entire land mass of the United States, ensures complete coverage of the U.S. farm population. The Area Frame Survey provides accurate estimates of crop acres and is the primary basis for the June Acreage report. The area frame is also used to measure the incompleteness of the list frame.

Sampling from the area frame is a multi-step process. First, all land in each state is classified into land use categories by the intensity of cultiva tion using a variety of map products, satellite imagery, and computer software packages. These land use classifications range from intensively cultivated land to marginally cultivated grazing land to urban areas. The land in each use category is then divided into segments ranging from about 1square mile in cultivated areas to 0.1square mile in urban areas. This allows intensively cultivated land segments to be selected with a greater fre quency than those less intensively cultivated.

Nearly 12,000 area segments are selected nation wide for the large scale survey conducted each June. Using maps and aerial photos that show the exact site and boundaries of each sample segment, interviewers locate and interview every operator with land inside the segment boundaries. They obtain information on the crops planted in each field, livestock inventory, and quantities of grain in stor age.

A considerable amount of data is also available from other organizations, both private and public. This administrative data is used to evaluate the accuracy of production estimates and to determine the final estimates. The information becomes available during the marketing year but often after the prelimi nary production estimates are determined. Some examples of administrative data follow.

Utilization data. Information about imports, exports, soybean crush, and industrial use are available from the Bureau of the Census. These data are used in a balance sheet that starts with carryover stocks from the previous year and the current production estimate, which measures total supply. At the end of the marketing year, when subtracting utilization data from the supplies at the beginning of the crop year, the result should correspond closely with the ending stocks. If there is a large unexplained difference between survey stocks and indicated stocks from the balance sheet, then the previous year acreage, yield, and production survey and stocks data are reviewed to determine if revisions should be made.

Slaughter statistics. NASS receives data through the Food Safety and Inspection Service about the number of animals inspected at slaughter opera tions. These data are used to monitor the accuracy of the livestock production statistics.

Price statistics. Extensive use is made of USDA's Agricultural Marketing Service market news data to prepare the monthly average prices received from the sales of livestock species. Also, Bureau of Labor price indices are used to measure the relative changes in prices paid for production input items.

NASS is a world leader in the use of statistical methodology to produce statistics about agriculture. NASS statisticians provide consultative services to a large number of developing countries around the world, helping them develop statistical information about their agriculture. NASS has also been a leader in making information available through electronic media. Globalization of markets is expanding as buyers and sellers have nearly instant access to market information from around the world.

The 1997 U.S. Census of Agriculture is being conducted by NASS and began in December 1997. The Census of Agriculture functions have been transferred from the Census Bureau in the Depart ment of Commerce to NASS in the Department of Agriculture. This will link all major statistical ser vices for agriculture. All county, state, and U.S. level data provided in previous Census periods will be made available from the 1997 Census of Agricul ture.

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