US election 2020: Why do different news sites have different tallies?

Promo image showing ballots, a clock and a question mark

Why do different news sites have different tallies?

If you are seeing different tallies at the top of the live coverage from various news sites, you might well be confused.

The BBC is projecting that Joe Biden will take Wisconsin, in line with our US sister network CBS.

With 99% of the votes counted, Biden currently has a lead there of just over 20,000 on Donald Trump. The tally above now includes the state's 10 electoral college votes.

Our projection that Joe Biden is the presumptive winner in Wisconsin reflects the situation now. If, as the Trump campaign has requested, a recount takes place, we will report that and the result - and if necessary, we'll change our projections accordingly.

For the 2020 election, the BBC is using data supplied via Reuters, from polling firm Edison Research, which does the field work for the exit polls and works with US television networks in the National Election Pool.

Edison Research has not projected a result for Wisconsin because the margin between Biden and Trump is less than one percentage point, meaning a candidate can request a recount.

You may have noticed that some other news sites are also projecting a win in Arizona for Biden, giving him an extra 11 electoral college votes. The BBC, again in line with CBS, considers the state too early to project.

With 87% of the vote in Arizona counted, Biden currently has a lead of about 68,000 over Trump.