Pollsters fear a statistical disaster

THE NAMES Kinnock and Major haunt this presidential campaign - not only because of the parallel so comforting to Mr Bush, that here too a conservative party in power for a dozen years might yet again squeak back. For the myriad US polling organisations there is another fear: could they get it as spectacularly and embarrassingly wrong as their British counterparts in the run-up to the general election five months ago?

Superficially, a similar disaster might appear in the making. On one thing alone do polls since the Republican Convention agree, that Governor Bill Clinton still leads. But the size of that lead differs wildly: from 3 points in one 'quickie' survey immediately afterwards, to - variously - 6 points, 9 points, 11 points, 15 points, and most lately, according to the Washington Post and ABC yesterday, a gigantic 19 points.

And how could it be otherwise, the layman observes, when the samples are so small, normally between 750 and 1,000 individuals from a population of 250 million. That is the least of the pollster's worries: 'A few drops of blood are enough for an accurate blood test,' points out Frank Newport of the Gallup Organisation. Thus it is with political polling.

The technique of 'equal probability of selection' in a random sample is a computer-guided science designed to produce a cross- section of an entire country. Polling is normally spread over two to four days to remove other aberrations. 'We are only taking a snapshot of public opinion, not predicting a result two months in advance,' say the pollsters. But, they insist, the snapshot is as accurate as the obligatory 'doctors' warnings' permit.

One such 'warning' of course is statistical margin of error. In the the case of the Post/ABC survey, based on a a sample of 768 registered voters, this margin is plus or minus 4 per cent. This means that Mr Clinton's true score might be 51 per cent, not 55, and Mr Bush's 40 instead of 36 per cent. In that case the Democrat lead would be only 11 per cent, more or less in line with other recent polls.

And as the small print says, 'sampling error is only one of many potential sources of error'. These more subtle factors include the phrasing of questions, even the order in which they are asked. As an undeclared candidate for the White House, Ross Perot always fared better when people were questioned about their preference in a three-way race after being asked to choose between Mr Bush and Mr Clinton alone.

Then there are the 'don't knows'. People tend not to like admitting they do not have an opinion. Offered a blunt choice between two candidates, even undecided potential voters mostly opt for one or the other, meaning that ratings can be artificially inflated or deflated.

This year, arguably, that danger is larger than ever. Old party loyalties are frayed. Early in the campaign season, unusually high proportions of voters said they were dissatisfied with the choice on offer. The volatility of subsequent polls indicates that support for candidates may still be shallow. For that reason, as well as the British precedent, the political pros are unusually wary. 'This time we're not paying as much attention to the numbers, said one Democrat consultant, 'but going with our gut feelings.'

On balance the US presidential polls have a good track record, certainly better than their British equivalents. Not since Harry Truman's surprise win in 1948 have they suffered a serious embarrassment. The Kennedy-Nixon contest of 1960, they said, was too close to call - and it was. But even Jimmy Carter's narrow win in 1976 was correctly predicted. The trick, says Mr Newport of Gallup, is to keep polling up to the last moment.

Start your day with The Independent, sign up for daily news emails
Have you tried new the Independent Digital Edition apps?
ebooksA celebration of British elections
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?
Independent Dating

By clicking 'Search' you
are agreeing to our
Terms of Use.

iJobs Job Widget
iJobs General

Recruitment Genius: Senior Digital Marketing Consultant

£28000 - £45000 per annum: Recruitment Genius: A Senior Digital Marketing Cons...

Recruitment Genius: Assistant Stores Keeper

£16640 - £18500 per annum: Recruitment Genius: An Assistant Stores Keeper is r...

Recruitment Genius: Claims Administrator

£16000 - £18500 per annum: Recruitment Genius: This is an excellent opportunit...

Recruitment Genius: Software Developer - C# / ASP.NET / SQL

£17000 - £30000 per annum: Recruitment Genius: Developer required to join a bu...

Day In a Page

Fishing for votes with Nigel Farage: The Ukip leader shows how he can work an audience as he casts his line to the disaffected of Grimsby

Fishing is on Nigel Farage's mind

Ukip leader casts a line to the disaffected
Who is bombing whom in the Middle East? It's amazing they don't all hit each other

Who is bombing whom in the Middle East?

Robert Fisk untangles the countries and factions
China's influence on fashion: At the top of the game both creatively and commercially

China's influence on fashion

At the top of the game both creatively and commercially
Lord O’Donnell: Former cabinet secretary on the election and life away from the levers of power

The man known as GOD has a reputation for getting the job done

Lord O'Donnell's three principles of rule
Rainbow shades: It's all bright on the night

Rainbow shades

It's all bright on the night
'It was first time I had ever tasted chocolate. I kept a piece, and when Amsterdam was liberated, I gave it to the first Allied soldier I saw'

Bread from heaven

Dutch survivors thank RAF for World War II drop that saved millions
Britain will be 'run for the wealthy and powerful' if Tories retain power - Labour

How 'the Axe' helped Labour

UK will be 'run for the wealthy and powerful' if Tories retain power
Rare and exclusive video shows the horrific price paid by activists for challenging the rule of jihadist extremists in Syria

The price to be paid for challenging the rule of extremists

A revolution now 'consuming its own children'
Welcome to the world of Megagames

Welcome to the world of Megagames

300 players take part in Watch the Skies! board game in London
'Nymphomaniac' actress reveals what it was really like to star in one of the most explicit films ever

Charlotte Gainsbourg on 'Nymphomaniac'

Starring in one of the most explicit films ever
Robert Fisk in Abu Dhabi: The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers

Robert Fisk in Abu Dhabi

The Emirates' out-of-sight migrant workers helping to build the dream projects of its rulers
Vince Cable interview: Charging fees for employment tribunals was 'a very bad move'

Vince Cable exclusive interview

Charging fees for employment tribunals was 'a very bad move'
Iwan Rheon interview: Game of Thrones star returns to his Welsh roots to record debut album

Iwan Rheon is returning to his Welsh roots

Rheon is best known for his role as the Bastard of Bolton. It's gruelling playing a sadistic torturer, he tells Craig McLean, but it hasn't stopped him recording an album of Welsh psychedelia
Morne Hardenberg interview: Cameraman for BBC's upcoming show Shark on filming the ocean's most dangerous predator

It's time for my close-up

Meet the man who films great whites for a living
Increasing numbers of homeless people in America keep their mobile phones on the streets

Homeless people keep mobile phones

A homeless person with a smartphone is a common sight in the US. And that's creating a network where the 'hobo' community can share information - and fight stigma - like never before