On Thursday, USDA will release its June Acreage Report, arguably one of the most market-moving reports of the year, thanks to its planted acreage estimates for each crop. That gives analysts and growers alike a better idea of how big--or small--the harvest could be this fall for various crops.
But have you ever wondered how USDA collects the data that goes into this report? According to James Johanson, the national hay statistician for USDA's National Agriculture Statistics Service, the Acreage report is based on the results of two different types of surveys, both of which are important to the accuracy of the report.
One of the survey methods used is called "list frame." This style of survey is conducted four times per year. Survey questions are sent to the list of more than 70,000 farmers in the NASS database, according to Johanson. A number of them are called on the phone, but some still receive questions in the mail. Johanson says this type of survey will never be a complete sampling: farm operations can go out out of business or new farmers aren’t on the NASS registry right away, for example.
That's the reason for the second, more thorough "area frame" method.
With this approach, USDA employees known as numerators physically visit 10,975 segments of land, which are typically one square mile in size. It adds up to an in-depth sampling that includes approximately 7 million acres.
“We have aerial maps of [the segments], and numerators go that piece of land and account for every acre on that map,” explains Johanson. The numerators not only determine if the land is still in agricultural use and what crops are being grown there, they also note when acres are taken out of production for building construction or other purposes.
“This survey is complete because we know all the acres in the U.S.,” Johanson says. “It’s a much more face to face interview.”
It's also a very expensive method. The area frame survey is done only in June because it is so labor-intensive and costly. In South Dakota alone, USDA has nearly 30 numerators to gather the data, according to Johanson.
Have you ever been surveyed by NASS, either by phone or mail or in person for the area frame method? Let us know in the comments.