Random-Digit Dialing (RDD)

Random-digit dialing (RDD) refers to a set of techniques for drawing a sample of households from the frame or set of telephone numbers. The telephone number is the sampling unit that is the link to the household and its members. While the specific sampling techniques employed to draw RDD samples have changed over time, the three most influential RDD techniques are briefly described in this entry. RDD is distinguished from other telephone sampling methods because RDD selects the sample from the frame of telephone numbers, whereas the other methods select from lists of numbers in directories or commercial lists. The ability to sample all telephone households, not just those households on a list, is one reason for the popularity of RDD sampling. This entry ends ...