Sampling Methods in Agriculture

The U.S. Department of Agriculture was created in 1862 and the first U.S.D.A. crop report appeared in July 1863. Department statisticians relied on the expert judgment of voluntary crop reports in each county to supply information on crop conditions, production and yields and livestock inventories. These nonprobability measures were converted to official estimates based on relationships to census year or, later, the historic relationships between reports and the final revised estimates based on administrative check data. Probability samples now play the dominant role in the generation of agricultural statistics. Information provided to the public is contained in about 300 national reports and 9,000 state reports issued by NASS each year on more than 150 crop and livestock items, numbers and sizes of farms, farm labor and wage grades, and prices received and paid by farmers. This paper describes past sampling methods and describes current sampling methods used by NASS.