UPDATE (3:45 PM): Note that the success rates cited below do not account for the dozens and dozens Coleman challenges that have gone into the "blue folder" -- these are challenges not to the marks on the ballot but "process" challenges related to its propriety (such as whether the ballot's duplicate is missing). If we count the blue folder ballots as unsuccessful challenges, then Coleman's success rate is more like 7% -- however, it would be premature to do that since we simply don't know enough about them.
UPDATE (3:30 PM): Coleman was having a really terrible run of things for an hour or so there after lunch, with something like 5 or 6 challenges upheld out of more than 100 ballots evaluated. Most of these ballots were from Minneapolis and other Democrat-friendly places in Hennepin County, so this is perhaps no surprise. Overall, his success rate is now closer to ~10-11% than ~12-13%.
Also, please do not take any of the numbers you see here as gospel. Everyone is working off some or another kind of best guestimate.
With the Canvassing Board today having begun ruling on ballot challenges made by the Coleman campaign, we may now have a slightly better idea of where we stand in Minnesota's recount process.
Through lunchtime today, by my highly unofficial count, Coleman has won 33 of his 265 challenges, or 12.5%. By contrast, on Tuesday and Wednesday, Al Franken won 115 of his 393 challenges, or 29.4% -- again, by my highly unofficial count. (That Franken's success rate is much higher is not surprising since he had significantly fewer challenges outstanding)
The guys at The Uptake reported earlier today that Coleman has 1,021 challenges presently outstanding to the Canvassing Board. If he continues to win challenges at his current rate, he'd wind up with 127 successful challenges.
Franken apparently has some challenges that have yet to be resolved too. These are so-called "blue folder" ballots that were challenged for process (e.g. the absence of a duplicate ballot) rather than a voter intent reasons. There are something like 20-30 Franken ballots in the blue folder, which at a 29% success rate would net to another 7 ballots or so, bringing his total to 122 successful challenges.
If Coleman wins 127 challenges and Franken wins 122, that would mean a net of 5 votes for Coleman. If the Franken campaign's estimate was correct that it was winning the re-count by 4 votes assuming that all challenges would be rejected, that would produce a Coleman win by a grand total of ... one vote!
However, there remain any number of contingencies that make these estimates highly imprecise:
1. There were some challenges made by each candidate that apparently ended in the opponent's pile ... some Coleman challenges, for instance, in Franken's stack of ballots. I am confused by these and have tried to avoid counting them for now, but they could certainly make a difference of 5-10 ballots at the margins.
2. Coleman in particular has had a lot of "blue folder" ballots, which will not be addressed until after Christmas. Although my hunch is that very few blue folder challenges are liable to be successful (they probably point toward issues that are outside of the Canvassing Board's jurisdiction), it is hard to know for certain.
3. Both campaigns are now talking about adding back challenges that they had previously withdrawn.
4. We don't know if the Coleman challenges counted so far are representative of his efforts as a whole. (For what it's worth, the Board has not yet addressed any Coleman challenges from Minneapolis, St. Paul, or Duluth, which are highly blue cities that may lower Coleman's success rate).
5. There is no way to independently verify the Franken campaign's estimate that it was ahead by 4 ballots assuming that all challenges would be rejected.
6. We have not accounted for "fifth pile" absentee ballots that, if and when they are counted, could produce a net gain of as many as 100 votes (or more) for Franken.
7. Pretty much everything that has happened so far, and everything that happens from here on out, can and quite possibly will be the subject of a court challenge.
But other than that, we've got it all figured out...