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United States Department of Agriculture
National Agricultural Statistics Service

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  County Data FAQs

What is a list frame sample?

The list frame contains the names and addresses of all known farms and ranches NASS has obtained from various sources. Each farm is classified by operation characteristics such as number of corn acres or number of cattle. Large farms (e.g., Iowa farms with more than 5,000 acres of cropland) are sampled at high rates, while small farms (e.g., farms with less than 50 acres of cropland) are randomly selected at very low rates. A sample of about 75,000 farms is selected for each of the quarterly Crops and Hogs (June, September, December and March) surveys. Sample sizes for the January Cattle and Sheep surveys are 50,000 and 10,000 farms, respectively.

Data from the area and list frame samples are expanded and combined using multiple-frame statistical methodology which ensures that all farms are represented in the summary totals and that each farm is included only once. These samples are designed to produce estimates at the State and/or U.S. levels only.


Last modified: 06/02/09