What’s Still Left to Count, and Why Hasn’t a Winner Been Called?

There are only a handful of provisional ballots counted in Pennsylvania so far, mainly in Republican, rural areas. But these ballots do support the possibility that Mr. Trump could fare better than usual in the provisional vote. So far, he has won the provisional vote in these counties by a margin of 75 percent to 24 percent, versus a 70-29 lead in the non-provisional vote — or about a net 10-point improvement among these ballots.

If this 10-point improvement were to hold statewide, perhaps Mr. Trump could hope to win these ballots by 10 points or so. This would still leave him far short of victory. But the decent numbers for Mr. Trump in heavily Republican areas could leave the decision desks wanting to confirm that Mr. Trump won’t outperform by even more elsewhere in the state. After all, there’s more room to outperform in areas where he did worse.

That said, there are early indications that Mr. Trump will not fare so well elsewhere in the state. The Allegheny County executive said the early provisional ballots, of which there are 17,000, have been trending toward Mr. Biden by a 50-point margin.

Another reason it’s at least a little complicated to analyze the provisional ballots: We don’t have great data on their number or geographic distribution. The state has said there are at least 100,000, but the reporting is somewhat murky. There is not a county-by-county account of the provisional ballots, and it is not clear that the 100,000 includes the estimated number of provisionals from every county.

That said, the reporting we do have indicates that these provisional ballots are disproportionately in Democratic counties. Philadelphia said that “most” of its remaining 40,000 votes were provisional or overseas and military ballots.

Even if we conservatively estimate that there are only 20,000 provisional ballots in Philadelphia, that would still represent twice its share of the statewide vote if there are 100,000 statewide. That would make sense, as the city usually represents a disproportionate share of the provisional vote in the state. In 2016, Hillary Clinton added more than 20,000 votes to her tally in Philadelphia in the weeks after the election. Pittsburgh’s Allegheny County says there were 17,000 provisional ballots, which would again be well above the state average.

Similarly, the data from the Trump counties that do appear to have counted provisional ballots suggests most of the provisional vote will be in Democratic areas. The provisional ballots counted in Republican areas so far represent 0.7 percent of the total votes cast. If there are at least 100,000 provisionals, they’ll represent 1.5 percent of the total vote. The lower share in Republican areas so far suggests that there will be a higher share in Democratic areas, to make up for it.