Refining Cellular Phone Samples Using Switch Centers in a Multiregional Survey

• Activity Number: 422
• Type: Contributed
• Date/Time: Tuesday, July 31, 2012 : 2:00 PM to 3:50 PM
• Sponsor: Section on Survey Research Methods
• Author(s): Machell Town*+ and Carol Pierannunzi and Ashley Hyon and William Garvin
• Companies: CDC and CDC and Marketing Systems Group and CDC
• Keywords: Cellular Phone Sampling ; Switch Centers ; Phone Towers ; Cellular Phone Geography

Abstract

One benefit of using landline telephone samples has been the ability to define geographic area using phone prefixes. Recently, numbers have become portable, and landline numbers have been changed to cellular phones. These changes have made prefixes less reliable in terms of geographic location. As surveys move to larger proportions of cellular samples, the need for other methods to obtain geographic information becomes more salient. Switch centers may be used as a proxy to ascertain likely locations of cellular users regardless of the prefix. Switch centers are associated with cellular numbers at the point at which phone numbers are activated, providing a "home base" location for each number within a cellular sample. This research uses 2011 telephone survey data of 38,000 respondents from eight regions located within four states to determine whether the use of switch centers increase the likelihood of reaching eligible adults within targeted areas. Results show that switch center information can significantly increase the likelihood that eligible respondents are contacted within targeted areas. Geographic data displays illustrate tower locations and success rates for eligibility.