| 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 Department 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 agricultural 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 important 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 published 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 agriculture, 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.
Data Sources and Estimation Procedures
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 telephone.
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
complete 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 cultivation 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 1 square mile in cultivated areas to 0.1 square mile
in urban areas. This allows intensively cultivated land segments to be
selected with a greater frequency than those less intensively cultivated.
Nearly 12,000 area segments are selected nationwide 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 storage.
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