What weeks of early-voting data tell us about how Democrats and Republicans are turning out in 2024

Why might voters in more Democratic-leaning areas cast their votes later than in areas more supportive of Republicans? One possible explanation is the availability of “satellite voting locations” in some Virginia jurisdictions. These are additional locations, beyond the general registrar’s office of a county or a city, where voters can cast early in-person ballots starting later in October. Such satellite voting locations may make early in-person voting accessible in more populous areas, which tend to be more Democratic-leaning. We will be watching closely to see whether those differences by area even out, or possibly reverse, over the next couple of weeks as satellite voting begins.

If we continue to observe turnout lagging in Democratic areas compared with Republican areas after satellite voting begins, it would lead us to do more investigation about whether consistent Democratic voters appear to be less mobilized than normal this election cycle.

Why these patterns matter for the NBC News Decision Desk

Part of why the NBC News Decision Desk watches absentee voting so closely is its implications for the sequencing of how votes get reported on election night. The fact that Democrats were more likely to cast mail and early in-person ballots than Republicans made our work on the Decision Desk more challenging than normal in 2020.

We are accustomed to the fact that counties report election results at different speeds on election night. In some states, smaller, largely rural counties tend to report their votes first, while in others, larger, mostly urban counties are the first to report. We have long used models that try to account for such unevenness by analyzing whether the counties that have reported more votes tended to lean more Democratic or Republican in past elections compared with counties that have reported fewer votes. The models help us assess what the current reported results suggest about the likely final outcomes.

Before 2020, such models did not adequately account for the fact that counties also do not report different results by vote mode at the same speed. In some states, counties initially report the mail and early in-person votes and then the Election Day votes. In others, the order is flipped.

As it became clear in 2020 that Democrats were going to disproportionately vote by mail or vote early in person and Republicans were going to disproportionately vote on Election Day, we had to quickly improve our models to account not only for differences in the rates of reporting over counties, but also for differences in which vote modes had been counted. And while we are now in a better place to deal with that issue, it will still generally take us longer to project races in states where there are substantial partisan differences in voters’ use of mail and early in-person voting and differences in the speed of reporting by vote mode.

However, seeing the data out of Virginia makes us cautiously optimistic that we may observe less partisan differences by vote mode in 2024 than in 2020, at least in states like Virginia that have extensive early in-person voting.