The Viewing Data In addition to the data from these official Nielsen homes, the agency uses paper surveys during the sweeps periods in February, May, July, and November. With this method, they gather mail-in viewing information from thousands of households outside the 56 largest U.S. media markets.
To find their sample, Nielsen selects a county, then specific towns within that county, then specific homes within the designated area. They reach out and ask each of the chosen homes to participate in the program.