The United States is one of the world's largest producers and exporters of major field crops including wheat, rice, coarse grains (corn, barley, sorghum, and oats), oilseeds (soybeans, peanuts, canola, sunflowers, and other minor oilseeds), and cotton. Unexpected changes in the outlook for production of a major U.S. crop can lead to sharp movements in both domestic and global market prices. If sustained, large price volatility can lead to significant resource adjustments in the agricultural sector and possibly to large changes in outlays under U.S. farm support programs. The potential for market disruptions and financial loss led to the creation of a statistical bureau within the U.S. Department of Agriculture (USDA) in 1863, just a year after USDA was established. This statistical bureau eventually became the National Agricultural Statistics Service (NASS). NASS and its USDA precursors were created to provide independent, objective, reliable, timely, and accurate market information for the agriculture industry. This report provides an overview of NASS. First, it reviews the origins, legislative authority, and funding for NASS. Then, the report describes the survey methodology used by NASS to generate crop production forecasts and estimates for U.S. crops at both the state and national level. Third, this report describes the systematic evolution that occurs over the course of a growing season for both the survey methodology and the annual sequence of NASS reports that are used to convey the crop production forecasts to the U.S. agricultural sector. Fourth, this report describes how NASS survey methodology is extended to collect county-level crop area and yield estimates. This fourth section also includes a discussion of emergent issues related to low producer response rates to NASS surveys and the subsequent discrepancies in neighboring county yield estimates and farm program payments. Finally, the report discusses how evidence on market price reaction to USDA crop production forecasts indicates that there is no visible pattern of bias or error. NASS conducts a series of surveys throughout the year to assess farmer planting decisions and production outcomes. The resulting NASS crop production and stock estimates underlie USDA and private analysis that affects markets throughout the year. They provide a benchmark in the marketplace because of their comprehensive nature, objectivity, and timeliness. For example, NASS estimates provide the foundation for USDA's global commodity supply and demand balance sheets published in the monthly World Agricultural Supply and Demand Estimates ( WASDE ) report. The public benefits of NASS data are notable, and the literature on those benefits was recently reviewed by the Council on Food, Agricultural and Resource Economics, which highlighted how public information on market prices and quantities helps improve market efficiency. NASS data are considered crucial to both policymakers in government and those making marketing and investment decisions, as well as to the design and implementation of U.S. farm support programs. The reliability and accuracy of USDA's crop supply and demand estimates play a prominent role in the smooth function of agricultural commodity supply chains, including forward contracting, stock management, and commodity futures exchanges. This reliability helps to ensure a more informed and stable marketplace. The quality of NASS crop acreage and production estimates depends on a high level of participation by agricultural producers. In recent years declining grower response rates to NASS surveys have diminished the statistical reliability of NASS estimates. In particular, low response rates to NASS surveys in some counties have led to unexpected and inconsistent farm program payment rates under the new county-based revenue support program—Agricultural Risk Coverage (ARC-CO)—established under the 2014 farm bill ( P.L. 113-79 ). This issue is discussed in more detail in the section " Increasing Nonresponse Degrades County Yield Calculations " of this report. These discrepancies have generated considerable concern about whether the new revenue program is working as intended or whether this is simply a data problem that needs to be addressed. Barring any near-term fix by USDA, lawmakers could elect to address county-to-county payment disparities in the context of the next farm bill. NASS's mission statement states that the agency "provides timely, accurate, and useful statistics in service to agriculture." In fulfillment of this mission, NASS collects and publishes current national, state, and county agricultural statistics. NASS is also responsible for administration of the Census of Agriculture, which occurs every five years and provides comprehensive data on the U.S. agricultural economy. NASS is one of four agencies—along with the Agricultural Research Service, the National Institute of Food and Agriculture, and the Economic Research Service—in USDA's agricultural research, education, and extension mission area. NASS is headquartered in Washington, DC, but maintains a network of 12 regional offices, including a National Operations Center in St. Louis, MO, and 50 state field offices through cooperative agreements with state departments of agriculture or universities. NASS survey data are used to produce forecasts of area, yield, production, value, and stocks for major crop and livestock products, as well as for estimates of the historical number of farms and land in farms, land rental rates and values, farm labor usage, fertilizer and chemical usage, computer usage and ownership on farms, and farm production expenditures. In addition to the several hundred nationally focused statistical reports from its headquarters each year, NASS state statistical offices issue some 9,000 reports and news releases annually that highlight or expand on information from the national reports. In addition, NASS conducts and releases the Census of Agriculture every five years. In support of this work, NASS maintains a fairly comprehensive working list of farms and ranches in the United States, one of its unique federal roles. NASS also performs important reimbursable agricultural survey work for other federal agencies, state governments, and producer organizations and provides technical assistance for agricultural statistics programs in developing countries. Among its activities, NASS's NOC houses the National Operations Division (NOD). NOD is responsible for several critical survey support activities, including maintenance of the list sampling frame, interviewer training for both field and telephone enumerators, centralized data collection via telephone interviewing (NOD has 154 calling seats and conducted over 1.1 million telephone calls in 2015), and processing of the paper-based survey questionnaires that are completed and returned by mail from farmers and ranchers. In 2015, the Forms Processing Group at NOD handled over 436,000 forms. It also processes a significant portion of the Objective Yield Samples collected by field personnel from winter wheat, corn, soybean, and cotton field plots. NASS operations are guided by an Advisory Committee on Agriculture Statistics. The purpose of the committee is to advise the Secretary of Agriculture on the scope, timing, content, etc., of the periodic censuses and surveys of agriculture, other related surveys, and the types of information to obtain from respondents concerning agriculture. The committee also prepares recommendations regarding the content of agriculture reports and presents the views and needs for data of major suppliers and users of agriculture statistics. In addition to guidance from the committee, NASS is subject to USDA's Information Quality Guidelines that apply to any information disseminated by NASS. The guidelines emphasize the confidentiality of respondents and objectivity of analysis. Annually, NASS—in coordination with the World Agricultural Outlook Board (WAOB), ERS, Agricultural Marketing Service (AMS), Foreign Agricultural Service (FAS), and the U.S. Census Bureau—hosts a meeting of key data users. The annual Data Users Meeting provides an open forum for data users—both government and nongovernment—to ask questions and provide feedback about the entire USDA statistics program, including data products from NASS. At the 2016 meeting held in Chicago on October 18, the Farm Service Agency (FSA) participated for the first time and addressed questions about NASS county-level data availability, particularly in relation to the issues that emerged with regard to payments under the ARC county-level program. This issue is discussed in more detail in the section " County-Level Crop Production Estimates " of this report. NASS's responsibilities are authorized under the Agricultural Marketing Act of 1946 (7 U.S.C. 1621-1627) and the Census of Agriculture Act of 1997 ( P.L. 105-113 ; 7 U.S.C. 2204g). Under this broad authority and the discretion of the Secretary, NASS exists and performs its data collection and dissemination functions in support of the U.S. agricultural sector. In particular, because of its transparent and objective methodology, NASS data contribute to the orderly association among the consumption, supply, marketing, and input sectors of agriculture. Over the years, various other laws have designated specific authority to the Secretary for data collection and publication regarding particular commodities and reports. These include laws concerning the collection of agricultural production and price data for apples (7 U.S.C. 411b), cotton (7 U.S.C. 476), peanuts (7 U.S.C. 951), commodity reports (7 U.S.C. 1421d), distribution and marketing of agricultural products (7 U.S.C. 1626), mandatory reporting for dairy products (7 U.S.C. 1637b), and data on the environment and water quality (7 U.S.C. 136i-2). Additional laws cover confidentiality of information and data security, research and international programs (7 U.S.C. 3291), cooperative agreements (7 U.S.C. 3318 and 7 U.S.C. 2242a), public printing and documents (44 U.S.C. 1302), and penalties for disclosure and false reports (19 U.S.C. 1905). The COA originated as part of the 1820 national decennial census, when U.S. marshals began to ask how many people within each household were engaged in agricultural pursuits. The Census of Agriculture Act of 1997 ( P.L. 105-113 ; 7 U.S.C.