Why Vote Counting Takes Longer in Some US States

Ballot acceptance and processing rules are not the same across US states, and that is why the speed of vote counting also differs from state to state. In some states a large share of the result is known shortly after voting ends, while in others the full tally takes much longer to emerge.

Several factors lie behind slower counts, including the prevalence of voting by mail and the rules governing how early-vote ballots are processed and counted. Because those rules vary by state, so does the rhythm of the count.

In most states, election workers may open ballot envelopes and verify voter eligibility before election day arrives. As a result, a large part of the preparatory work is finished before election day itself.

In about half the states, including Florida, ballots may also be scanned and stored in counting machines before the election. Those ballots can then be counted as soon as voting ends and added to the results on election night.

In some states, however, including Michigan and Wisconsin, election workers are not permitted to open mail-in ballot envelopes before the election. There, everything from opening envelopes to counting has to happen after election day.

In previous elections, questions were raised in parts of those states when large numbers of votes arrived at night and many ballots were added to the count at once. Such episodes have been described as 'late night' votes arriving and as a 'ballot dump'.

Some states also accept mail-in ballots that arrive after election day. That can delay the counting and the publication of total vote figures, so the final picture in those states takes longer to emerge.