Random digit dialing (RDD) is a method for selecting people for involvement in telephone

statistical survey Survey methodology is "the study of survey methods". As a field of applied statistics concentrating on human-research surveys, survey methodology studies the sampling of individual units from a population and associated techniques of survey da ...

s by generating

telephone number A telephone number is a sequence of digits assigned to a landline telephone subscriber station connected to a telephone line or to a wireless electronic telephony device, such as a radio telephone or a mobile telephone, or to other devices f ...

s at

random In common usage, randomness is the apparent or actual lack of pattern or predictability in events. A random sequence of events, symbols or steps often has no order and does not follow an intelligible pattern or combination. Individual ran ...

. Random digit dialing has the advantage that it includes unlisted numbers that would be missed if the numbers were selected from a

phone book A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into ele ...

. In populations where there is a high

telephone A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...

-ownership rate, it can be a cost efficient way to get complete coverage of a geographic area. RDD is widely used for statistical surveys, including

election An election is a formal group decision-making process by which a population chooses an individual or multiple individuals to hold public office. Elections have been the usual mechanism by which modern representative democracy has operat ...

opinion polling An opinion poll, often simply referred to as a survey or a poll (although strictly a poll is an actual election) is a human research survey of public opinion from a particular sample. Opinion polls are usually designed to represent the opinions ...

and selection of

experimental control A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable (i.e. confounding variables). This increases the reliability of the results, often through a comparison betw ...

groups. When the desired coverage area matches up closely enough with

country code Country codes are short alphabetic or numeric geographical codes (geocodes) developed to represent countries and dependent areas, for use in data processing and communications. Several different systems have been developed to do this. The term ...

s and

area code A telephone numbering plan is a type of numbering scheme used in telecommunication to assign telephone numbers to subscriber telephones or other telephony endpoints. Telephone numbers are the addresses of participants in a telephone network, r ...

s, random digits can be chosen within the desired area codes. In cases where the desired region doesn't match area codes (for instance,

electoral district An electoral district, also known as an election district, legislative district, voting district, constituency, riding, ward, division, or (election) precinct is a subdivision of a larger state (a country, administrative region, or other poli ...

s), surveys must rely on telephone databases, and must rely on self-reported address information for unlisted numbers. Increasing use of mobile phones (although there are currently techniques which allow infusion of wireless phones into the RDD sampling frame), number portability, and

VoIP Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet t ...

have begun to decrease the ability for RDD to target specific areas within a country and achieve complete coverage.

References

Sources

* * {{cite journal, url=http://aje.oxfordjournals.org/cgi/content/full/153/11/1119, archive-url=https://archive.today/20130415134014/http://aje.oxfordjournals.org/cgi/content/full/153/11/1119, url-status=dead, archive-date=2013-04-15, title=Comparison of Telephone Sampling and Area Sampling: Response Rates and Within-Household Coverage, publisher=American Journal of Epidemiology, date=2001-06-01, author=Donna J. Brogan1, Maxine M. Denniston, display-authors=etal Survey methodology Telephone numbers

See also

References

Sources