ADDISON COUNTY — The 2017 USDA Census of Agriculture, which was released this spring, was the 29th such survey, going all the way back to 1840 (it wasn’t always conducted every five years).
Production and sales figures are taken from the year in which the census was conducted. Market value of inventories, including land and buildings, are taken on Dec. 31 of that year.
Much has changed over the decades, and some changes, when they’re made, make it impossible to compare certain statistics from one census year to another.
Typically, however, those sorts of changes do not affect the way county numbers compare with state numbers in any given category.
The most significant weakness of the USDA Census of Agriculture is probably the decline in participation by farmers.
The USDA and its state affiliates go to a great deal of trouble to gather agricultural information every five years, and they spend a lot of time and publicity to encourage farmers to participate.
But farmers are getting less and less interested.
The response rate in 2007 was 78.2 percent. In 2012 it fell to 74.6 percent. In 2017 it fell again, to 71.8 percent.
The math laid out in an appendix of the 2017 census seems to explain, in part, how the USDA responds to incomplete data — as well as to errors and other issues — but as the department suggests, nothing can take the place of 100 percent participation.