Most questionaires like the ag cencus use information that seems relatively meaningless to some to "profile" the subjects being quizzed. They use statistical information such as approximate value of your equipment along with acreage farmed, estimated value of crops raised, ect, to determine what "average" is. It's not so much their being interested in the value of your equipment as it is just how you fit in the grand scheme of things. Most employers have questions on their applications that do the same end. It's almost ridiculous to think the government is concerned about how much you paid for your latest tractor. Do you suppose that's critical information as to US farm policy? NOPE! They just want a better picture of where you fit in the big picture, and just how your locale stacks up against farms and farmers in other parts of the country.
I doubt seriously any major policy will hinge upon how much I paid for my used hay rake, nor is there someone sitting in a dark office in the basement of the Capital building who needs to know specifically how much I have invested in my old combine. They just need generalizations and averages to reach INFORMED EDUCATED desicions rather than just guessing.