Controls in NYC were ascertained by RDD, using the telephone exchanges (area code plus three-digit prefixes) of breast cancer cases who received medical care at the participating hospitals in previous years for sampling, frequency matched by 5-year age groups and race.
The local telephone exchange is Sandbach (code WMSBH), with several companies providing a variety of Internet broadband services, including Broadband ADSL since 2000, and Broadband ADSL Max since 2006 (estimated speed 3.5Mb).
Case-patients and controls were matched by age group, postal or zip code, and telephone exchange to control for age and socioeconomic status.
An RDD sample of this type is generated by first identifying each area code and telephone exchange used in the targeted geographic region in direct proportion to number of listed residential households.
Hats off to Evelyn Sheinkopf for her interesting article on old Los Angeles telephone exchanges ("Know the Code," So SoCal, Nov. 10).
It would be intelligent to make a rule that a telephone exchange cannot be split into two different area codes.
How absurd and how shortsighted can a world-class telephone company become if it allows the splitting of a telephone exchange (528 and 526, for example) into two different area codes (915 and 845)?
A good example of an encoding like this is the encoding of telephone numbers: the telephone exchange can, on input of a string of digits that it recognises, immediately connect you; once an acceptable code from a prefix-free set has been input, no other acceptable code can follow it.
"And the telephone exchange is Gramowitz," the old joke goes.
Conner, the former telephone exchange operator, also forgave.
Telephone lines between army and government offices were cut, and the telephone exchange was occupied.
