heritage “A Correct Prediction So Surprising It Would Not Be Believed” — UNIVAC and the 1952 Presidential Election
By Robert Colburn, IEEE History Center
The story has been told and
retold for decades: how CBS Television News used
a UNIVAC computer to predict the 1952 U.S.
Presidential election returns and — when the
computer accurately predicted the Eisenhower
landslide at around 8:30 in the election night
broadcast — the prediction was doubted, and
only hours later did CBS reveal that the
prediction had been accurate. It has become a
classic cautionary tale of the dangers of
allowing human preconception to interfere with
logic and evaluation of facts.
There is more to the story. The
exact timeline of when UNIVAC's initial
prediction was made is not certain, but what is
important is that UNIVAC's correct prediction of
a landslide victory was ostensibly ignored until
much later in the broadcast because of
journalistic prudence and lack of confidence in
the accuracy of the results.
Dr. Ira Chinoy, whose
examines the use of computers in broadcast
journalism, estimates that the celebrated initial
prediction of the Eisenhower landslide was made
closer to 9:15.
At 8:30, only slightly more than one million
votes had been tallied; it took until at least
9:15 pm for three million votes to be
transmitted from CBS to the Remington Rand
factory in Philadelphia. CBS was receiving vote
tallies from the wire services and teletyping
them to Remington Rand’s factory in
Philadelphia. Additional time was needed to
input the data and to run the programs.
The 8:30 CBS segment merely
gave the television audience a visual tour and
introduction to UNIVAC; the second UNIVAC
segment of the evening at 9:30 asked for a
prediction, but the machine was not yet ready.
By that point in the television coverage, the
human commentators were already commenting on
the surprising Eisenhower strength in the early
returns. On the basis of pre-election polls,
the race between Eisenhower and Stevenson had
seemed to be close (Eisenhower held a slight
edge), so the use of a
state-of-the-art computer to predict what was
expected to be a very close election had
generated a lot of popular interest.
At some point relatively early
in the evening, UNIVAC predicted an Eisenhower landslide
victory. However, the
UNIVAC programmers decided that the prediction
was too risky to release because it contradicted
what the pollsters had been saying previous to
the election about a tight race.
At 10:30, which was the third
on-air UNIVAC segment, the computer predicted twenty-eight states for
Eisenhower and twenty for Stevenson. This was a
softer prediction, and was in line with what the
CBS commentators had already been telling their
television audience. It was the initial correct
prediction of an overwhelming Eisenhower win
that the UNIVAC
programmers decided not to release because it
contradicted the poll numbers.
The 11:30 UNIVAC on-air
prediction caused more drama. It reversed its
earlier prediction, calling 24 states each for
Eisenhower and Stevenson, and a slim 270 to 261
Electoral College vote margin for Eisenhower.
But by 11:45, the prediction had been
corrected and UNIVAC predicted 100 to 1 odds of
an Eisenhower victory.
UNIVAC made its predictions
based on the difference between vote tallies and
the expected vote in cities and counties, based
on a statistical model extrapolated from past
elections. By applying this deviation in places
that had already voted to those which had not
yet voted, an estimate of the present election
could be obtained based on past tallies in those
places. One of the ironies of the election of
1952 was that the returns from Massachusetts,
one of the crucial early-reporting states, were
incorrectly reported to UNIVAC. That UNIVAC was
nonetheless able to make accurate predictions.
The UNIVAC used by CBS was the
fifth UNIVAC machine made. In the autumn of
1952, UNIVAC-5 was still in the Philadelphia
factory of Remington Rand waiting for its future
installation at the Lawrence Livermore
Laboratories. Because UNIVAC itself was too
large to be moved conveniently, a dummy control
console was set up in the CBS studio in Grand
Central Terminal, New York City for visual
effect, its lights blinking evocatively thanks
to delay switches ordinarily used for making
Christmas tree lights flash on and off.
There was some irony that a
machine which debuted in the public spotlight of
national TV would go on to do classified weapons
work. UNIVAC contained mercury delay lines,
which allowed it to store 1,000 words (45 bits
each) as electric pulses in tubes of mercury. Up
to one million characters could be stored and
accessed on magnetic tape. It was these tapes,
replacing punched cards, which made the UNIVAC
revolutionary, and which gave it a tremendous
speed advantage because it could access its own
data instead of needing to wait for cards to be
loaded. It could perform four hundred and
sixty-five multiplications per second and had a
clock speed of 2.25MHz.
A brief Youtube video of the CBS prediction can
be seen here.