According to The Business Research Lab
Nationally, 27.6% of households have unlisted numbers.
In many cities the unlisted rate is over 50%.
California is especially bad, with most cities over 50% (Los Angeles
is 56% unlisted).
http://www.busreslab.com/articles/article3.htm#phone
According to Survey Sampling, Inc, a leading provider of telephone
samples to business,
"No one currently collects data on the properties of unlisted
households, but it is generally assumed that they are households with
lower income. The highest demographic correlation with unlistedness is
age. Younger people, due to frequent address changes, are more likely
to be unlisted."
"...phone books fail to represent the important population of people
whose phone number is unlisted. In some markets, the percentage of
such people is over 60%."
http://www.surveysampling.com/ssi.x2o$ssi_gen.faq?id=3
Other data from Survey Sampling:
In the US, the percentage of ex-directory households in metropolitan
areas tends to be higher than the national average.
According to many studies, minority households are more likely to have
unlisted telephone numbers than the population as a whole
There is a chart of unlisted telephones in Canada by province at
http://www.worldopinion.com/the_frame/2001/nov_2.html
I don't have the documentation for this, but I know from having worked
extensively with telephone samples 10 and 20 years ago that the
percentage of unlisted numbers is up dramatically from the low teens
in the 1980's.
Another problem is the increased use of cellular phones as the primary
household telephone.
Survey Sampling (1-203-255-4200) or another professional telephone
sampling company could supply you with current percentages and trends,
also with ways to overcome the problems
if you need to reach unlisted households.
Search strategy: telephone sample unlisted number; "survey sampling"
unlisted number
Nellie Bly |
