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FORTUNE.COM // JUNE .1 .19
BIG DATA EVERY 10 YEARS, the U.S. Census
Bureau conducts a nationwide survey
that sets the terms for the country’s democracy.
The questionnaire yields rich data, including
names, street addresses, ages, races, ethnicities,
and other details. That creates a troubling
problem: A savvy sleuth can use public records to
link detailed private information to specific
individuals.
The bureau, tasked with releasing summaries
of the results while simultaneously protecting
privacy, faces a catch-22. “Every time you publish
a statistic, you leak information,” as Simson Gar-
finkel, a computer scientist with the bureau, told
a Census advisory committee in May. If people
believe their responses will not be kept private,
they may not respond. And with the planned
addition of a new, sensitive question to the 2020
Census, which asks about citizenship, privacy
gains urgency.
There’s a problem, though: The usual methods for
preserving people’s privacy no longer suffice. Start-
ing in 2016, researchers used statistical tools and
public data to exactly reconstruct 46% of the 2010
Census’s confidential
database. Allowing for
plus or minus a year
leeway in age, they re-
assembled records for
71% of the population.
By combining the bu-
reau’s published tables
with other commer-
cially available data
sets, the researchers
found they could
confidently reidentify
17% of the population,
linking names to other
attributes.
John Abowd, chief
scientist at the Census
Bureau and leader of
the 2016 study, says
the old privacy safe-
guards are ineffective:
“Turns out, nobody is
well enough buried in
the haystack.” To ad-
dress the issue, Abowd
has implemented cut-
ting-edge “differential
privacy” techniques
for the 2020 Census.
The process intention-
ally injects noise, or
random variables,
into the system, an
approach used by tech
giants like Google to
anonymize user data.
The result: Would-be
database unmaskers
cannot learn people’s
details with granular-
ity using Census data.
It’s a tradeoff
between precision
and privacy. While
some social science re-
searchers grouse that
the new approach will
impede their work,
the backlash to a large
data breach could
be far worse for the
future of the Census.
Census Security
Why the government is adopting cutting-edge
privacy techniques for the upcoming Census.
By Robert Hackett
CELLULAR’S FIFTH
GENERATION IS
STILL IN INFANCY
CONNECTED
HUZZAH! The wireless
industry has finally
delivered on years of
promises and hype
and is offering the
first superfast 5G
networks. Sort of. In
April, Verizon became
the first U.S. carrier
to offer 5G service via
a phone. Reviewers
measured speeds as
high as 600 mega-
bits per second, 10
to 20 times faster
than on a typical 4G
LTE network. But the
problem for Verizon’s
5G service, and a
similar offering also
due soon from AT&T,
is restricted cover-
age owing to the
limitations of using
high-wavelength
radio bands that
don’t travel as far as
current-day cellular
networks. Nationwide
coverage is a year
or more away. So
for most consumers
hungry for superfast
mobile downloads, it’s
still hurry up and wait.
—AARON PRESSMAN
CENSUS: BILL WUNSCH
—THE DENVER POST VIA GET T Y IMAGES; PHONES: COURTESY OF SAMSUNG
