Biggest Polling Misses in Election History

1948 US Presidential Election

Gallup and Roper stopped polling weeks before Election Day, certain Dewey had it locked up — so certain that the Chicago Tribune printed 'DEWEY DEFEATS TRUMAN' before all votes were counted. Truman held up that newspaper with a grin, and the photo became the eternal symbol of pol

Year: 1948Country: United StatesPredicted Outcome: Dewey wins easilyActual Outcome: Truman winsApprox. Polling Error: 10 ptsShock Factor: 10/10Clear Methodology Flaw Identified?: ✓

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2016 US Presidential Election

National polls had Clinton up comfortably, and models gave her upwards of 70-90% win probability, but Trump's narrow sweep of Wisconsin, Michigan, and Pennsylvania flipped the map overnight. It sparked a full industry reckoning over undercounted non-college-educated white voters.

Year: 2016Country: United StatesPredicted Outcome: Clinton wins comfortablyActual Outcome: Trump wins Electoral CollegeApprox. Polling Error: 5 ptsShock Factor: 9/10Clear Methodology Flaw Identified?: ✓

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1936 Literary Digest Poll

The Literary Digest mailed out ten million straw-poll ballots and confidently predicted a Landon landslide over FDR — only for Roosevelt to win 46 of 48 states. The magazine's sample, skewed toward car and phone owners during the Depression, effectively destroyed its own credibil

Year: 1936Country: United StatesPredicted Outcome: Landon wins landslideActual Outcome: FDR wins in historic landslideApprox. Polling Error: 19 ptsShock Factor: 10/10Clear Methodology Flaw Identified?: ✓

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Brexit Referendum (2016)

Bookmakers and most pollsters had Remain comfortably ahead right up to polling day, with betting markets pricing in over 80% odds of staying in the EU. Leave's narrow win stunned markets, crashed the pound overnight, and triggered David Cameron's resignation within hours.

Year: 2016Country: United KingdomPredicted Outcome: Remain winsActual Outcome: Leave wins narrowlyApprox. Polling Error: 4 ptsShock Factor: 9/10Clear Methodology Flaw Identified?: ✓

added by IJR

2015 UK General Election

Every major pollster called it a dead heat, with newspapers preparing coalition-negotiation coverage for a hung parliament. Instead David Cameron's Conservatives swept to an outright majority, prompting the British Polling Council to launch a formal inquiry into what went wrong.

Year: 2015Country: United KingdomPredicted Outcome: Hung parliament, tied raceActual Outcome: Conservative majorityApprox. Polling Error: 6 ptsShock Factor: 8/10Clear Methodology Flaw Identified?: ✓

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2020 US Presidential Election

After the 2016 embarrassment, pollsters retooled — yet still predicted a comfortable Biden blowout with double-digit leads in some swing states. Biden won, but by razor-thin margins in Georgia, Arizona, and Wisconsin, proving the underlying bias hadn't been fully fixed.

Year: 2020Country: United StatesPredicted Outcome: Biden wins by wide marginActual Outcome: Biden wins narrowlyApprox. Polling Error: 4 ptsShock Factor: 7/10Clear Methodology Flaw Identified?: ✓

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1992 UK General Election

Polls throughout the campaign showed Neil Kinnock's Labour Party either tied or ahead, and Kinnock's premature victory rally became infamous. John Major's Conservatives instead won a fourth straight term, and the 'Shy Tory Factor' entered the political lexicon.

Year: 1992Country: United KingdomPredicted Outcome: Labour wins or tiesActual Outcome: Conservative majority under MajorApprox. Polling Error: 8 ptsShock Factor: 8/10Clear Methodology Flaw Identified?: ✓

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2015 Israeli Election

Final polls showed Isaac Herzog's Zionist Union edging ahead of Benjamin Netanyahu's Likud, prompting Netanyahu's famous election-day warning about Arab voters 'coming out in droves.' Likud instead won decisively, a gap so large it forced Israeli pollsters to defend their exit-po

Year: 2015Country: IsraelPredicted Outcome: Zionist Union leadsActual Outcome: Likud wins clearlyApprox. Polling Error: 4 ptsShock Factor: 7/10Clear Methodology Flaw Identified?: ✓

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Colombia 2016 Peace Referendum

Every published poll showed the FARC peace deal passing by a landslide, some by margins of 30 points or more. Voters narrowly rejected it instead, sending negotiators back to the table and becoming a textbook case of urban-sample bias missing rural and undecided sentiment.

Year: 2016Country: ColombiaPredicted Outcome: Yes (peace deal) wins comfortablyActual Outcome: No wins narrowlyApprox. Polling Error: 19 ptsShock Factor: 9/10Clear Methodology Flaw Identified?: ✓

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1970 UK General Election

Harold Wilson's Labour government entered polling day with a comfortable lead in nearly every survey and called the snap election expecting an easy win. Edward Heath's Conservatives pulled off a surprise victory instead, one of the first elections to badly embarrass Britain's you

Year: 1970Country: United KingdomPredicted Outcome: Labour (Wilson) winsActual Outcome: Conservative (Heath) winsApprox. Polling Error: 7 ptsShock Factor: 7/10Clear Methodology Flaw Identified?: —

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2002 French Presidential Election (First Round)

Polls universally predicted Socialist incumbent Lionel Jospin would cruise into a runoff against Jacques Chirac. Instead far-right candidate Jean-Marie Le Pen edged out Jospin for second place, a shock so severe it triggered mass street protests across France before the runoff.

Year: 2002Country: FrancePredicted Outcome: Jospin advances to runoffActual Outcome: Le Pen advances insteadApprox. Polling Error: 5 ptsShock Factor: 9/10Clear Methodology Flaw Identified?: ✓

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2019 Australian Federal Election

Every published poll for the entire term had Labor ahead, leading commentators to call it 'the unlosable election' for Bill Shorten. Scott Morrison's Coalition won instead, prompting Australia's polling industry to shut down its main aggregated polling model in the aftermath.

Year: 2019Country: AustraliaPredicted Outcome: Labor wins comfortablyActual Outcome: Coalition (Morrison) winsApprox. Polling Error: 5 ptsShock Factor: 8/10Clear Methodology Flaw Identified?: ✓

added by IJR2019 Australian federal election

2004 US Presidential Election Exit Polls

Leaked early exit polls on election afternoon showed John Kerry comfortably ahead in key states, sending Democratic campaign staff into premature celebration. George W. Bush won those same states hours later, exposing a systematic Democratic skew in same-day exit poll response ra

Year: 2004Country: United StatesPredicted Outcome: Kerry leads (early exit polls)Actual Outcome: Bush wins re-electionApprox. Polling Error: 3 ptsShock Factor: 6/10Clear Methodology Flaw Identified?: ✓

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1980 US Presidential Election

Most polls into late October showed a tight race between Jimmy Carter and Ronald Reagan, some even giving Carter a slight edge. A late debate performance triggered a massive last-minute swing, and Reagan won 44 states in a landslide nobody's models saw coming.

Year: 1980Country: United StatesPredicted Outcome: Close Reagan-Carter raceActual Outcome: Reagan wins in a landslideApprox. Polling Error: 8 ptsShock Factor: 7/10Clear Methodology Flaw Identified?: —

added by IJR

2004 Indian General Election

The ruling BJP's confident 'India Shining' campaign was backed by polls and pundits predicting a comfortable return to power for Atal Bihari Vajpayee. The Congress-led opposition won instead, a result widely blamed on urban-focused surveys missing rural economic discontent.

Year: 2004Country: IndiaPredicted Outcome: BJP-led NDA re-electedActual Outcome: Congress-led UPA winsApprox. Polling Error: —Shock Factor: 7/10Clear Methodology Flaw Identified?: —

added by IJR2004 Indian general election

2015 Greek Bailout Referendum

Polls in the final days suggested a razor-thin, possibly Yes-leaning outcome on accepting Europe's austerity terms, with markets bracing for a close call either way. Greeks instead voted decisively 'Oxi' (No) by a wide margin, catching European leaders and pollsters flat-footed j

Year: 2015Country: GreecePredicted Outcome: Too close to call, narrow Yes leanActual Outcome: No (Oxi) wins decisivelyApprox. Polling Error: 10 ptsShock Factor: 6/10Clear Methodology Flaw Identified?: —

added by IJR