With at least 89 of the 110 election authorities showing totals that are considered final (mostly just small counties remaining) and the race having been conceded I have stopped updating the tracker.

It's impossible to say exactly how many votes were counted after election night but we can make some approximations. I didn't find the county by county totals for the Treasurer's race until sometime on the afternoon of Wednesday the 5th, and there are still some counties that haven't made final updates in our tracker but if you look at the list of updates I tracked there were at least 132,000 new votes over what was reported by the AP on election night. The tracker currently lists roughly 3.527 million total votes in this race so roughly about 4% of the total vote was reported after election night.

Despite the fact that this race was decided by the razor thin margin of just a few thousand votes (roughly one quarter of one percent) this late counted vote had a decided Democratic lean. Frerichs won this late counted vote 56%-40%-4%, a 16 point spread and in doing so gained an advantage of roughly 21,000 raw votes (at current count).

This leads to two questions:

1. Why did this happen?
2. What assumptions can we make for future elections?

Let's look at these questions by type of vote. First, why were there so many votes that were not counted until after election day?

• Early vote and mail vote that arrived by election day - in the past these were often counted prior to 7pm on election night and then these numbers were the first posted results you would see while waiting for all the precincts to be counted. However it was determined that the law does not allow for the clerks to count these votes before 7pm on election night and the Attorney General sent a notice to all of the election authorities to offer specific guidance on the issue. Many election authorities were still able to get these votes counted and included in their election night totals but not all. A number of election authorities were still counting these votes and adding them to their publicly available totals for a few days after the election. The General Assembly may want to review the law and consider if there are options that would allow the clerks to count these votes in advance if doing so would not harm election integrity. If the law was changed to allow all of these votes to be counted at a convenient time for the clerks then we may not see a repeat of this in the future, if not these votes may not be counted on election night depending on each election authority's size, capacity and execution.
• Election day votes - by the end of election night 109 of the 110 election authorities had 100% of their precincts reporting, only Chicago had 23 of its 2,069 precincts left to report so the vast majority of these votes were included in the election night totals. We haven't had major problems counting election day ballots since 2006 so for future elections I would expect these vote totals will be available on election night.
• Late arriving mail votes - any ballot with a post mark before election day can be legally valid and counted if it arrives at the election authority up to 14 days after the election. Most election authorities counted the mail ballots they had as of election day and included them in their election night totals. However for the ballots that arrived after election day most did not provide regular updates of these votes (a few did, but not many). Instead most election authorities waited until the 18th and just posted one large update with these new totals. This will likely be true for future elections.
• Same day registration votes - this was the first year for same day registration, unregistered voters were allowed to register and vote on election day at select locations. The law that authorized same day registration expired so unless it is reauthorized it will not be part of future elections. These votes were included in the provisional ballot totals and were not added to the publicly available vote totals until two weeks after the election.
• Provisional ballots - there will always be provisional ballots and those votes won't be included in the totals until they have been properly evaluated on a case by case basis. These votes weren't included in the publicly available totals until the 18th. There was some anecdotal evidence that in Chicago many voters who had recently registered to vote had to vote provisional because they weren't listed on the voter rolls at the polling places on election day. If that was the case there may have been many more provisional ballots than normal (and some valid voters may have been disenfranchised), better clerical work could reduce this number for future elections.

Since vote by mail appears here to stay there will always be late arriving vote by mail ballots, although the amount will vary from election to election. Also, if same day registration is renewed then those votes will likely continue to be counted after election night. On the other hand you could potentially reduce the number of votes that need to be counted after election night by giving the clerks the power to count early vote and on time Vote By Mail votes somewhat earlier in the day on election day and better clerical work could reduce the number of traditional provisional ballots that need to be reviewed. So while there will continue to be votes that need to be counted after election night any number of changes could make that universe smaller than what we had in this election.

The next question has to do with partisan advantage. According to our non-exhaustive list of vote total changes since election night these votes had a 16 point advantage for Democrat Mike Frerichs (56%-40%-4%) despite the fact that this race overall had a razor thin margin of roughly one quarter of one percent. Can we expect the Democrats to have the same advantage among late arriving votes in future elections? Again, let's look at this question by each type of vote:

• Late arriving mail votes - there are two questions to consider here: 1) is there a partisan skew for procrastinators? and 2) what are the mechanics of executing a Vote By Mail program that could impact the timing of vote arrival? On the first question I don't think there is a partisan skew to procrastination. Perhaps polling or an academic study will show that there is but until we see some supporting data I don't think it's reasonable to assume that one party's voters will wait until the last minute while the other party's voters will mail their ballots in well ahead of time. The more likely factor in the timing of mail ballot arrival has to do with the mechanics of the VBM programs. I was told that both the Democratic and Republican parties in Illinois has significant VBM programs this year to make it as easy as can be for their most likely supporters to vote by mail. I was also told anecdotally that in this election the Republicans started their program before the Democrats. Both parties likely reached out to their most likely supporters who requested a VBM ballot to remind them to mail in their ballot. Obviously the earlier and more frequent those reminders took place likely affected when some of these ballots were returned. If both parties followed essentially the same process but one started earlier than the other then it would affect the timing of VBM ballot arrival. There is no guarantee that in the next election the timing of these efforts will remain the same or even that one or both parties will put the same amount of effort into Vote By Mail. For example in the next election one party could decide to focus on early voting instead of VBM. It's in every party/candidate's best interest to have their voters get their ballots in as early as possible so neither party/candidate necessarily wants to have a large number of their voters among the late arriving mail ballots. There is no guarantee that the timing of the VBM ballot arrival in this election will be the same in future elections and since the timing is likely to be the most significant determining factor of partisan skew there is no guarantee that either party will have a significant advantage in the late arriving VBM ballots in future elections.
• Same day registration votes - if same day registration is renewed and used again in future elections I think this will still vary by some factors unique to each election authority. If same day registration is limited to select locations how convenient are those locations? Next, and probably more important, in that jurisdiction which parties/candidates have workers or volunteers actively working the precincts and how well versed are those workers/volunteers on the rules of same day registration and are they actively encouraging unregistered voters to participate? Unregistered potential voters are likely the least motivated/informed voters in the electorate. Of all of the people who could potentially know that same day registration exists I would expect the subset of people who couldn't find the time to register in advance the least likely to be aware of same day registration. I wouldn't expect a groundswell of organic same day registration voters, that universe will probably be defined by the efforts of county clerks to make it available and campaign/party precinct workers to take advantage of it. Having said all of that this universe will probably still lean Democratic since the demographics of unregistered voters leans Democratic as well: the young, the frequent movers, ethnic minorities and urban moreso than suburban moreso than rural. Still, a well organized suburban Republican effort could outproduce Democratic numbers if the Democrats were not similarly well organized.
• Provisional ballots - people who have lived at the same address for many years (and have been registered to vote there) don't vote provisional. Provisional ballots skew towards the recently newly registered and/or the voters who have to frequently re-register. Like the list above this universe has demographics more likely to skew towards the Democratic party.

Some of the late arriving ballots will skew towards the Democrats, specifically the traditional provisional ballots and possibly the same day registration ballots (but not certainly) while the late arriving mail ballots could skew towards either party depending on the get out the vote programs of each party and their candidates. There is no guarantee that future elections will see late counted votes skewing towards the Democrats by 16 points as they apparently did in this Treasurer's race according to the best numbers we have available.

If a future election is as close as this one was at the end of election night we're just going to have to study it in detail again and see what characteristics that are unique to that election will have an impact on the final result.