How to Conduct a Telephone Survey for Gold Standard Research

Telephone surveys are still considered the gold standard for rigorous public opinion polling and market research.  The reason is that virtually every household in the U.S. can be reached by telephone, and therefore we have careful methods of determining the probability that any individual person is included in a sample to be surveyed.  Knowing this probability is at the core of statistical inference, which makes mathematical purists very happy.

Here are the steps involved in conducting a rigorous “gold standard” telephone survey of the U.S. population:

• You will need a sample of about 1,000 to 1,200 U.S. adults, which means you will need a list of at least 20,000 households to call.
• Generate your list of households using stratified random sampling (stratifying by region of the U.S.) from a list of land-line exchanges (there are currently  more than 69,000 of them).
• Add random digits to each exchange to create a complete telephone number – random digits ensure you will reach unlisted households.
• Determine a procedure to randomly select one adult in each household that you reach.  Asking to survey the adult who had the most recent birthday is one common procedure.
• Similar to the land-line sampling procedure, you will need to include a sample of randomly generated cell phone numbers.
• Try to call every number multiple times, varying the day and time of day at which you call.
• Weight the final data to adjust for sample imbalances on region, gender, age, race, ethnicity, marital status, education, number of adults in the household, number of landlines into the household, and presence of both landline(s) and cell phone(s).

For now, these are the procedures required to pass the rigor test of the most conservative methodologists, many of whom eschew Internet sampling.  But of course with telephone response rates declining dramatically and landlines disappearing quickly, the challenges of “gold standard” telephone research as outlined above may soon become insurmountable.  A recent research article in Public Opinion Quarterly concluded that sampling and coverage issues with both landlines and cell phone “call into question . . . the very future of telephone surveys.”

Whether you should launch a telephone survey or some other type of survey depends entirely on your objectives.  There are advantages and disadvantages to telephone surveys.  Knowing the steps involved and the pros and cons can help you make a smart decision.  Versta Research has deep experience conducting surveys by phone, Internet, mail, in-person, and in multiple combinations of these.  If you need help understanding and weighing your options, we would be happy to give you our best advice.

—Joe Hopper, Ph.D.