When news outlets make a race call on election night, it is an unofficial prediction that can change over time as more votes are counted. Each outlet has teams that work through the night and into the days following an election to collect data and calculate projections based on different sets of assumptions. News outlets make their predictions in order to provide their readers with up-to-the-minute analysis of the results.
The final results are certified by elections officials, who may take days or even weeks to process all the ballots. This includes recounts, if necessary.
In addition to recounts, there are several other steps that state elections officials must complete before they can certify official election results. The figure below outlines some of the common processes, but not all states follow these procedures exactly and the exact timeline can vary from year to year.
While most voters expect their preferred candidate to win, a surprising result can still elicit strong reactions from losers and winners. One reason for this is that prior research has shown that electoral expectations are in part driven by partisan biases (e.g. Delavande and Manski 2012; Dolan and Holbrook 2001). If a voter’s party or candidate is unexpectedly defeated, the cognitive dissonance between their preferences and the outcome can trigger a winner effect, wherein the losing side is less likely to believe that the result was fair, leading them to turn to claims of electoral fraud to resolve their confusion.