The task of counting and announcing vote results from over 100,000 precincts across the country — mostly within a few hours — requires a massive operation that involves hundreds of thousands of poll workers, election officials and observers.
We may think of a presidential election as a single nationwide contest, but how elections are administered varies across the 50 states and Washington, D.C. Even within states, different jurisdictions — counties, cities and so on — could have different administrative practices or logistics in the election process.
In most of the country, counties run elections. In a handful of states, particularly in New England, cities or towns administer them.
Nearly all of those jurisdictions provide multiple vote reports (updates to the vote count) on election night and in the following days. In the November 2020 election, NBC News received over 88,000 updates to its vote totals across 542 different races. More than 45,000 of those vote updates came before 2 a.m. ET on election night.
From 9:15 to 9:30 p.m. ET that night, NBC News received just over four updates per second, on average.
In all, NBC News will report vote results from 4,635 jurisdictions across the U.S. Here’s how it works, from how local governments count to how NBC News monitors, checks and displays the vote totals.
How do states and counties tabulate their vote results?
The vote results reported by NBC News are the product of hundreds of thousands of people working to accurately and efficiently count and report the results. The process begins at your local polling place or precinct. On Election Day 2020, there were over 107,000 physical polling places nationwide, staffed by nearly 700,000 poll workers, many of them volunteers.
After polls close in your state and the last voters have cast their ballots, poll workers begin to close the precincts and tabulate the votes. Each state has different requirements for the process, but the steps generally include turning off and securing voting machines and ensuring that the number of voters who checked in corresponds with the number of ballots cast.
Then, each precinct tabulates its vote results and reports those numbers to a central office in its county or town.
In some states, local precincts also count mail ballots from voters who live inside the boundaries of those precincts. Poll workers must scan them through tabulation machines either on Election Day, perhaps while the precincts are not busy, or after polls have closed.
In other places, mail ballots are counted centrally in a jurisdiction’s single facility instead of precinct by precinct. Some of those counties, such as Clark County, Nevada (home of Las Vegas), and Maricopa County, Arizona (home of Phoenix), provide partial reports at regular intervals. Others do not report any mail results until they have tabulated all the mail ballots.
For example, Milwaukee County in Wisconsin released its full tabulation of about 170,000 mail ballots at 4:40 a.m. ET on election night 2020, after it had worked its way through the whole batch.
How does NBC News receive and display counties’ vote tabulations?
In November, NBC News is covering 610 statewide and congressional races. To manage the task of collecting all those results in a relatively short amount of time, NBC News coordinates with ABC News, CBS News and CNN through the National Election Pool, or NEP. Since 2018, the NEP has received vote count data from Edison Research, a firm that specializes in collecting election data.
No centralized, federal government agency collects and reports vote results, so each state determines how it makes those results available. Many states have websites where anybody can access the real-time vote counts. Others have websites with results — but the numbers on election night are not as up to date as what is available from individual counties.
And some states do not have vote results pages that update on election night at all.
Edison Research collects the vote results state by state and county by county. When possible, it uses software to automatically detect updates and collect the vote counts from state or county websites. In other jurisdictions, Edison manually transcribes vote result data from PDFs into its tabulation system.
And because many jurisdictions do not post their results online on election night but the results themselves are public information, Edison also hires thousands of “vote reporters” to physically be at county or town election offices where they can get the totals after votes are tabulated.
After Edison processes the data, it is transmitted to NBC News and the rest of the NEP. That is when you will see vote numbers change on a television graphic or on NBCNews.com. That is also when NBC News’ Decision Desk sees the updated vote count and uses it in its process of determining when it can accurately project the winner of a race.
How does NBC News ensure the vote counts are correct?
Given the high volume of data being reported in a fairly short amount of time, it is not hard to imagine that mistakes can be made. Any process that involves hundreds of thousands of people transmitting millions of numbers has the potential for human-generated error from poor handwriting, typos, miscommunications and so forth.
What makes election results in this country trustworthy, however, are the countless fail-safes that detect and correct such mistakes.
The biggest of those fail-safes is vote certification. The results you see on election night are only unofficial counts, and they can change — typically by tiny amounts, like when overseas and military ballots are added to vote counts or when a state conducts a recount in a close race and re-examines disputed ballots. Only when a state certifies the results, which happens days or even weeks after Election Day, do they become final. And before certification, states require several postelection audit procedures, which double- and triple-check the accuracy of the counts.
On election night, there are other error-detection fail-safes at every stage of the vote counting process. They begin at the local precincts, where poll workers make sure that the “books balance” by verifying, for example, that the number of ballots cast in the precincts correspond with the number of voter check-ins.
Then, when a precinct reports its vote results to its state or county, it performs additional quality assurance checks. Does the number of votes in the precinct make sense when compared with its number of registered voters? Is the turnout rate comparable to the rates in nearby precincts? If any of those questions raise flags about a precinct’s count, the state or the county will resolve the concerns by consulting with the person in charge of the precinct or by re-checking the data before those votes are added to the county’s overall count.
Edison Research performs another set of data quality checks when it receives vote results. It looks for errors, like extra digits added to a candidate’s count or vote counts for two candidates getting flipped accidentally. If Edison’s error detection system suspects a report may include a mistake, the data gets held until a trained analyst can verify it with the state or the county.
Finally, NBC News’ Decision Desk also has its own set of data quality assurance tools, which compare the vote results to various administrative and historical data sources. If those tools detect anomalies, they are flagged to Edison and the NEP for further investigation. NBC News’ Decision Desk will not call a race until it is certain that the vote results are error-free.
