538, originally rendered as FiveThirtyEight, is an American website that focused on opinion poll analysis, politics, economics, and sports blogging in the United States.

The "average" of polls over an extended period (perhaps several weeks) would neither reveal the true state of voter preferences at the present time, nor provide an accurate forecast of the future.

It's also here [referring to another article], in the form of Pollster Scorecards, a feature which we'll continue to roll out over the coming weeks for each of the major polling firms, and which will explain in some detail how we arrive at the particular rating that we did for each one".

The polling database was compiled from approximately eight or ten distinct data sources, which were disclosed in a comment which I posted shortly after the pollster ratings were released, and which are detailed again at the end of this article.

[22] FiveThirtyEight gained further national attention for beating out most pollsters' projections in the North Carolina and Indiana Democratic party primaries on May 6, 2008.

In 2008, Rasmussen Reports had an apparently short-term partnership with FiveThirtyEight in order to include this unique methodology for generating poll averages in their "Balance of Power Calculator".

Silver's predictions matched the actual results everywhere except in Indiana and the 2nd congressional district of Nebraska, which awards an electoral vote separately from the rest of the state.

In Alaska, after a protracted counting of ballots, on November 19 Republican incumbent Ted Stevens conceded the seat to Democrat Mark Begich, an outcome that Silver had forecast on election day.

[26] In Georgia, a run-off election on December 2 led to the re-election of Republican Saxby Chambliss, a result that was also consistent with Silver's original projection.

[538 19] Later, Silver adapted his methods to address a variety of issues of the day, including health care reform, climate change, unemployment, and popular support for same-sex marriage.

[538 29] In spring 2010, FiveThirtyEight turned a focus on the United Kingdom general election scheduled for May 6, with a series of more than forty articles on the subject that culminated in projections of the number of seats that the three major parties were expected to win.

[538 41] Silver did not move his blog to the highest bidder, because he was concerned with maintaining his own voice while gaining the exposure and technical support that a larger media company could provide.

[39] The first column of the renamed FiveThirtyEight: Nate Silver's Political Calculus appeared in the Times on August 25, 2010, with the introduction of U.S. Senate election forecasts.

[40] Shortly after FiveThirtyEight relocated to The New York Times, Silver introduced his prediction models for the 2010 elections to the U.S. Senate, the U.S. House of Representatives, and state Governorships.

[538 48] On September 12, 2011, Silver introduced another writer: "FiveThirtyEight extends a hearty welcome to John Sides, a political scientist at George Washington University, who will be writing a series of posts for this site over the next month.

[538 49] While politics and elections remained the main focus of FiveThirtyEight, the blog also sometimes addressed sports, including the March Madness[538 50][538 51][42] and the 2012 NCAA Men's Basketball tournament selection process,[538 52] the B.C.S.

rankings in NCAA college football,[43] the NBA,[538 53][538 54][538 55] and Major League Baseball matters ranging from the 2011 attendance at the New York Mets' Citi Field[538 56] to the historic 2011 collapse of the Boston Red Sox.

[538 61][538 62] FiveThirtyEight published a graph showing different growth curves of the news stories covering Tea Party and Occupy Wall Street protests.

[538 65] On the morning of November 6, Election Day, Silver's model gave President Obama a 90.9% chance of winning a majority of the electoral votes.

[52] In its announcement of its acquisition of FiveThirtyEight, ESPN reported that "Silver will serve as the editor-in-chief of the site and will build a team of journalists, editors, analysts and contributors in the coming months.

He argued that by giving "Mr. Trump a 2 percent chance at the nomination despite strong polls in his favor ... they also arguably sapped the journalistic will to scour his record as aggressively as those of his supposedly more serious rivals".

Unlike virtually every other forecast we publish at FiveThirtyEight – including the primary and caucus projections I just mentioned – our early estimates of Trump's chances weren't based on a statistical model.

[70][71] FiveThirtyEight's model pointed to the possibility of an Electoral College-popular vote split widening in final weeks based on both Clinton's small lead in general polls, but also on Trump's improvement in swing states like Florida or Pennsylvania, mixed with Clinton's poor performance in several of those swing states in comparison with Obama's performance in 2012.

[72] The main issues pointed out by the forecast model was the imbalance of Clinton's improvement in very populated states like Texas, Georgia (projected safe for Republican) and California (projected safe for Democrats);[72] mixed with her inability to attract white voters without a college degree, an increasing demographic in swing states, in addition to a potential decline in turnout from minorities.

[72] Silver also focused on state-by-state numbers in so-called 'must-win' states like Ohio and Florida, plus a consideration of polls' margin of error in advantages of less than three points.

This included going with modular structure, a "ball swarm" design for the chart depicting each candidate's chances, and the addition of a "forecast mascot" named Fivey Fox.

Hullman also said of the design that the introduction of the mascot, in conjunction with the new simplified look of the page, was "perhaps the strongest indicator that Silver intends to emphasize uncertainty" in his coverage of the 2020 election.

"[86] Nonetheless, in April, Silver announced that he would be leaving the site amid widespread layoffs at ABC News, who said the website would be "streamlined" ahead of the 2024 election cycle; editor Chadwick Matlin was among the many laid off.

[93] Silver criticized Morris's model, describing it as at best ignoring the polls and giving Biden positive odds merely due to his incumbency, and at worst as being "buggy".

[93][94] The election forecast remained suspended for a month after Biden withdrew, before being replaced by a new model for Kamala Harris versus Trump that put more emphasis on polling.