40:56
- ABC News
- June 11, 2024
Trump, Biden tied in 538's new election forecast
Trump has a slight edge in the polls, but the fundamentals favor Biden.
40:56
At this point in the race, our margin of error for these state forecasts is huge. There are two reasons for this: First, it is early. As pollsters are bound to remind you many times between now and November, polls are snapshots of public opinion as it stands today, not predictions of vote share in the eventual election. To the extent they are predictions at all, they predict how people would vote if an election were held today — which, of course, it will not be.
In part, this oft-repeated caveat is a convenient way for pollsters to avoid catching flak for inaccurate numbers closer to the election. But there is an important truth to it: If a voter has not yet cast their ballot, there is the possibility they may change their mind. We also don't know exactly who is going to turn out in this election yet. All this means polls earlier in the election cycle are worse at approximating the final margin.
This is where forecasting models really become useful. Above everything else, 538 makes forecasts to quantify the uncertainty inherent in the election. Our study of historical presidential election polls finds that the margin between the two candidates shifts by an average of 9 percentage points between June and November. In practical terms, that means today's polls have a true margin of error of close to 20 points. And while recent elections have not had as much volatility, we can't assume 2024 will be the same way; it's possible that this year will be closer to the historical norm.
The second major source of error is the chance that polls systematically underestimate one of the candidates, as happened in the 2016 and 2020 presidential elections. We estimate that, even on Election Day, state-level polling averages of presidential general elections have an expected error of 4 points on the margin — meaning if the candidates are tied in the polling average, then on average we'd expect one to win by 4, and in rare cases they could win by 8!
Having such wide margins of error is not our way of absolving ourselves of responsibility if the election result is surprising. It's our way of giving you, the reader, a more informed understanding of the range of potential election outcomes than you'd get from a single poll (or even a polling average).
Over the last decade, it has become common to view election forecasting — and even polling — as purely making predictions of \"what will happen\" in the election. But we think forecasting models serve a greater journalistic purpose than a focus on prediction gives them credit for. For us here at 538, forecasting is an exercise in quantifying the reliability of various indicators of public opinion. Yes, that involves making predictions, but the real value of our work is the statistical analysis of the reliability of the numbers you are bound to see plastered all over print news media, social media and television over the next five months.
We think this is a different goal from making predictions for prediction's sake, or making a model that can \"call\" every state correctly. If you want someone to give you a prediction of who will win the election with absolute certainty, then look elsewhere. (And buyer beware.)
Instead, we think we offer a unique product that can help you be smarter about the way you think about the range of outcomes for the election. As the stakes of our politics increase, a carefully calibrated sense of what could realistically happen in November — in our case, from a forecast that properly distinguishes between normal and tail risk — becomes increasingly valuable.
On that note, I'll end with a few tips on how to read our forecast responsibly:
Watch the distributions. Our model simulates thousands of possible Electoral College outcomes based on the historical predictive error of the indicators we rely on. The top of our forecast page has a histogram of a random subset of these simulations, showing you which outcomes are likelier than others. We hope you get the impression that there is a wide potential range of outcomes, given all the error we're talking about.
Unlikely does not mean impossible. In 2020, polls performed worse than in any election since 1980. The average state-level poll conducted in the last three weeks of that election overestimated Biden's vote margin by 4.6 points — about 1.5 times the average 3-point bias for presidential elections since 1972. In a backtest of our current model, we would have assigned about a 20 percent chance to Biden winning 306 electoral votes (the number he actually won) or fewer in 2020. We think a similar miss this year would be statistically surprising, but a possibility people should mentally prepare for.
Changes in public opinion take time. We have done our best to make a model that reacts the appropriate amount to new polling data. \"Appropriate\" here means that the model will be conservative early on or when polls are bouncing generally around the same level, but also that it will be aggressive when polls appear to be moving uniformly across states — especially late in the campaign. However, as a properly Bayesian statistical model, the program that runs our forecast generates some amount of uncertainty about the parameters, resulting in unavoidable random error across our simulations. This means polling averages can change by a few decimal places day to day — and probabilities may jitter by around a point, which cascades down into uncertainty in our model. Don't sweat these small changes; instead, pay attention to bigger changes in the model over longer stretches of time.
Use all the information you (reasonably) can. Polls are reasonably good predictors of election outcomes. In fact, asking people how they are going to vote is about the best single source of information you can get if your goal is to figure out how people might vote. But polls are not the only source of information available to us. 538's forecast incorporates demographics, polls and the \"fundamentals\" all the way up to Election Day; our research has found this decreases the chance for uniform bias in our forecast.
Our forecast assumes normal election rules still apply. This is an important disclaimer about what our model is intended to do and what it is not. Because our model is trained on historical polling and election results, it is not intended to account for violations of normal political and election rules. We assume, for example, that if a voter legally casts a ballot, it will be counted accurately and fairly; that the electors a state elects to vote for a certain candidate in the Electoral College get to do so; that their votes are ultimately recognized by Congress; and that, as an extreme example, the election is administered on time, where officials say it will be administered and generally that people who show up to vote will be able to.
That is not to say that we dismiss the possibility of rule-breaking. From an editorial perspective, we stand ready to cover any attempts to undermine a free and fair election. But as a quantitative matter, our forecast is intended to explain variance in election outcomes based on the polls and other indicators, to serve as a supplement to polling averages and to put other political journalism in its proper context.
*Within the 95 percent confidence interval.
","canonicalUrl":"https://abcnews.com/538/trump-biden-tied-538s-new-election-forecast/story?id=110789256","legacySlug":"/news/story/trump-biden-tied-538s-new-election-forecast-110789256","noIndexNoFollow":false},"publishTime":"12:05","publishDate":"06-11-2024","updatedTime":"12:55","updatedDate":"06-11-2024","socialImage":{"alt":"Introducing 538's new 2024 presidential election forecast.","credit":"ABC News Photo Illustration","ratio":"16x9","url":"https://s.abcnews.com/images/538/ForecastLaunch_v01_DG_1717609248702_hpMain_16x9_1600.jpg","width":992,"height":558},"datePublished":"6/11/2024 12:05:00 GMT","video":{"live":false,"id":110789256,"headline":"Trump, Biden tied in 538's new election forecast","mediaAssetTitle":"PREZ-FORECAST-ANNOUNCEMENT","description":"Trump has a slight edge in the polls, but the fundamentals favor Biden.","duration":"40:56","posterImg":{"url":"https://s.abcnews.com/images/GMA/default-img-undefined.png","width":608,"height":342},"video":{"feed":"https://service-pkgabcnews.akamaized.net/opp/hls/abcnews/2024/06/240610_538_Monday_Podcast_DC_,500,800,1200,1800,2500,3200,4500,.mp4.csmil/playlist.m3u8"},"playlist":["132055565","131830882","130993584"]},"relatedItems":[{"contentType":"video","date":"April 15, 2026","headline":"American influencer found dead in Tanzania","section":"News","slug":"/video/132055565","id":"132055565","image":{"alt":"VIDEO: American influencer found dead in Tanzania","credit":"ABCNews.com","ratio":"1x1","url":"https://s.abcnews.com/images/GMA/260415_gma_norwood_ashlee2_732_hpMain_1x1_608.jpg","width":384,"height":384},"images":{"alt":"VIDEO: American influencer found dead in Tanzania","credit":"ABCNews.com","crops":[{"16x9":{"small":"https://s.abcnews.com/images/GMA/260415_gma_norwood_ashlee2_732_hpMain_16x9_608.jpg","medium":"https://s.abcnews.com/images/GMA/260415_gma_norwood_ashlee2_732_hpMain_16x9_992.jpg","large":"https://s.abcnews.com/images/GMA/260415_gma_norwood_ashlee2_732_hpMain_16x9_1600.jpg"}},{"9x16":{"small":"https://s.abcnews.com/images/GMA/260415_gma_norwood_ashlee2_732_hpMain_9x16_608.jpg","medium":"https://s.abcnews.com/images/GMA/260415_gma_norwood_ashlee2_732_hpMain_9x16_992.jpg","large":"https://s.abcnews.com/images/GMA/260415_gma_norwood_ashlee2_732_hpMain_16x9_1600.jpg"}},{"1x1":{"small":"https://s.abcnews.com/images/GMA/260415_gma_norwood_ashlee2_732_hpMain_1x1_608.jpg","medium":"https://s.abcnews.com/images/GMA/260415_gma_norwood_ashlee2_732_hpMain_1x1_992.jpg","large":"https://s.abcnews.com/images/GMA/260415_gma_norwood_ashlee2_732_hpMain_1x1_1600.jpg"}}]}},{"contentType":"video","date":"April 8, 2026","headline":"Ceasefire analysis, unanswered questions ahead","section":"News","slug":"/video/131830882","id":"131830882","image":{"alt":"VIDEO: Ceasefire analysis, unanswered questions ahead","credit":"ABCNews.com","ratio":"1x1","url":"https://s.abcnews.com/images/GMA/260408_gma_krl1_hpMain_1x1_608.jpg","width":384,"height":384},"images":{"alt":"VIDEO: Ceasefire analysis, unanswered questions ahead","credit":"ABCNews.com","crops":[{"16x9":{"small":"https://s.abcnews.com/images/GMA/260408_gma_krl1_hpMain_16x9_608.jpg","medium":"https://s.abcnews.com/images/GMA/260408_gma_krl1_hpMain_16x9_992.jpg","large":"https://s.abcnews.com/images/GMA/260408_gma_krl1_hpMain_16x9_1600.jpg"}},{"9x16":{"small":"https://s.abcnews.com/images/GMA/260408_gma_krl1_hpMain_9x16_608.jpg","medium":"https://s.abcnews.com/images/GMA/260408_gma_krl1_hpMain_9x16_992.jpg","large":"https://s.abcnews.com/images/GMA/260408_gma_krl1_hpMain_16x9_1600.jpg"}},{"1x1":{"small":"https://s.abcnews.com/images/GMA/260408_gma_krl1_hpMain_1x1_608.jpg","medium":"https://s.abcnews.com/images/GMA/260408_gma_krl1_hpMain_1x1_992.jpg","large":"https://s.abcnews.com/images/GMA/260408_gma_krl1_hpMain_1x1_1600.jpg"}}]}},{"contentType":"video","date":"March 12, 2026","headline":"Winter whiplash plunges temperatures along the East Coast","section":"News","slug":"/video/130993584","id":"130993584","image":{"alt":"VIDEO: Winter whiplash plunges temperatures along the East Coast","credit":"ABCNews.com","ratio":"1x1","url":"https://s.abcnews.com/images/GMA/260312_gma_zee_storm2_hpMain_1x1_608.jpg","width":384,"height":384},"images":{"alt":"VIDEO: Winter whiplash plunges temperatures along the East Coast","credit":"ABCNews.com","crops":[{"16x9":{"small":"https://s.abcnews.com/images/GMA/260312_gma_zee_storm2_hpMain_16x9_608.jpg","medium":"https://s.abcnews.com/images/GMA/260312_gma_zee_storm2_hpMain_16x9_992.jpg","large":"https://s.abcnews.com/images/GMA/260312_gma_zee_storm2_hpMain_16x9_1600.jpg"}},{"9x16":{"small":"https://s.abcnews.com/images/GMA/260312_gma_zee_storm2_hpMain_9x16_608.jpg","medium":"https://s.abcnews.com/images/GMA/260312_gma_zee_storm2_hpMain_9x16_992.jpg","large":"https://s.abcnews.com/images/GMA/260312_gma_zee_storm2_hpMain_16x9_1600.jpg"}},{"1x1":{"small":"https://s.abcnews.com/images/GMA/260312_gma_zee_storm2_hpMain_1x1_608.jpg","medium":"https://s.abcnews.com/images/GMA/260312_gma_zee_storm2_hpMain_1x1_992.jpg","large":"https://s.abcnews.com/images/GMA/260312_gma_zee_storm2_hpMain_1x1_1600.jpg"}}]}}],"relatedContentSection":"news","schemaContent":{"name":"Trump, Biden tied in 538's new election forecast","description":"Trump has a slight edge in the polls, but the fundamentals favor Biden.","duration":"40:56","uploadDate":"06-11-2024","publication":"06-11-2024","images":"https://s.abcnews.com/images/GMA/default-img-undefined.png","url":"https://service-pkgabcnews.akamaized.net/opp/hls/abcnews/2024/06/240610_538_Monday_Podcast_DC_,500,800,1200,1800,2500,3200,4500,.mp4.csmil/playlist.m3u8","contentUrl":"https://service-pkgabcnews.akamaized.net/opp/hls/abcnews/2024/06/240610_538_Monday_Podcast_DC_,500,800,1200,1800,2500,3200,4500,.mp4.csmil/playlist.m3u8","link":"https://www.goodmorningamerica.com/news/story/trump-biden-tied-538s-new-election-forecast-110789256"}},"playlist":[{"id":"132054443","contentType":"story","section":"news"},{"id":"132054798","contentType":"story","section":"news"},{"id":"132033010","contentType":"story","section":"news"},{"id":"131912713","contentType":"story","section":"news"},{"id":"131830583","contentType":"story","section":"news"},{"id":"131834976","contentType":"story","section":"news"},{"id":"131554765","contentType":"story","section":"news"},{"id":"131554815","contentType":"story","section":"news"},{"id":"131543053","contentType":"story","section":"news"},{"id":"131432442","contentType":"story","section":"news"},{"id":"131121474","contentType":"story","section":"news"},{"id":"131247079","contentType":"story","section":"news"},{"id":"131228784","contentType":"story","section":"news"},{"id":"131178806","contentType":"story","section":"news"},{"id":"131142257","contentType":"story","section":"news"},{"id":"131046664","contentType":"story","section":"news"},{"id":"131048076","contentType":"story","section":"news"},{"id":"131033212","contentType":"story","section":"news"},{"id":"130999943","contentType":"story","section":"news"},{"id":"130971027","contentType":"story","section":"news"}],"kvps":{"pgtyp":"article","lang":"en","sp":"goodmorningamerica","programmatic":"true","bundleId":"com.abcnews"}},"analytics":{"accountID":"wdgnewwdgnewgmaweb","ns":"gma","pageName":"gma:news:video","pageType":"video","globalSpecVersion":"v1.08","siteDifferentiator":"gma:site","tagID":"g_page01","userABCookie":"0","section":"news","title":"Trump, Biden tied in 538's new election forecast","pubTime":"08:05","pubDate":"06-11-2024","modTime":"08:55","modDate":"06-11-2024","taxonomyTags":"none","id":110789256,"editorialOtherSubjects":"","wordCount":"none","columns":"none","authors":"","authorsUnit":"none","authorsBureau":"none","subBrand":"Good Morning America","provider":"Good Morning America","videoName":"Trump, Biden tied in 538's new election forecast","mediaAssetTitle":"PREZ-FORECAST-ANNOUNCEMENT","videoId":110789256,"mediaOnPage":"video","legacySlug":"/news/story/trump-biden-tied-538s-new-election-forecast-110789256"},"taboola":{}},"request":{"headers":{},"httpVersion":"1.1","method":"GET","url":"/video/110789256","vary":{"host":"www.goodmorningamerica.com","cached":true,"path":"/video/110789256","forwarded-proto":"https","device":"desktop","userab":"0"}},"viewport":{"width":1260,"height":0},"user":{}};