Understanding Statistics

NASS Surveys: The Foundation of Estimates - Nationwide Enumeration and Integrated Surveys

Each June, NASS conducts a major multiple frame survey, in which farmers are visited by enumerators to get a firsthand accounting of their agricultural activities. This midyear survey collects data on crop acreage, grain stocks, number of farms and land in farms, livestock inventories, pigs farrowed, calves born, the farm economy, labor, and other items for State, regional, and national estimates.

The probability sample for June contains about 15,400 area segments --roughly 0.7 of 1 percent of the total land area in the 48 contiguous States -- which translates into interviews with roughly 52,000 farm operators. Enumerators also contact between 70,000 and 75,000 farmers and ranchers from the list frame.

After locating each operator, the enumerator explains the purpose and importance of the survey and asks a number of questions. The enumerator carefully records all of the operator's answers. Questionnaires are then sent to the SSO's, where they are checked for completeness and consistency.

Surveys at other times of the year combine a portion of the area frame farms visited at midyear with extensive list samples to obtain data to estimate crop and livestock inventories and production, and acres seeded for fall grain crops.

A major advantage of this program is that it reduces the number of times per year a producer must be contacted for information, thereby conserving resources and minimizing the burden on survey respondents.

Quality controls have been built into the data collection process to ensure the accuracy of survey results. These safeguards include careful selection and training of enumerators, use of detailed instruction manuals, careful field supervision, questionnaire checks, comparison of reported acreage with those measured on the aerial photographs, and follow-up visits to some segments.

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Last Modified: 05/04/2018