Incorporating Democratic Party Primary RCV tabulation in to Tabulator

[chughes297]

As mentioned on the call a few weeks ago, the Democratic parties in Wyoming, Kansas, and Alaska are planning on using the Universal Tabulator to determine the results of their RCV presidential primaries this year. Clear Ballot is providing the scanners for the election; I spoke with Don Deford, who works at Clear Ballot, last week about what they need from the tabulator to run the election. Right now it's possible to get very close to the 15% threshold required by the rules (electing six candidates in a bottoms up contest would get you very close with a 14.3% threshold; five candidates would, also, with a 16.67% threshold, but not precise enough if a candidate comes within .7% to 15%). So, the only missing feature from the Tabulator for the Primaries is the ability to set an arbitrary threshold.

As I mentioned, the Democratic Primaries use an arbitrary 15% threshold to award delegates. That is the threshold of election they'll use for the RCV contests too, paired with bottoms up RCV allocation. So the election will follow typical single-winner RCV rules, eliminating one candidate at a time (or batch eliminating candidates) and edistributing votes from those candidates until only candidates with 15%+ of the vote are left. I'm not certain of this but I believe that 15% is set based on the votes cast in the first round, and is not dynamic based on the number of valid votes in each round. (this isn't specified in the rules, unfortunately).

The Wyoming and Alaska primaries are scheduled for April 4, and Kansas is scheduled for May 2.

A few things i wanted to raise that need deciding:

• How should this arbitrary threshold option present itself to the user? Only if they select bottoms up? By selecting something labeled Democratic Presidential Primary? That selective appearance is not a function we've used before, though. Seems best to limit the availability of arbitrary threshold so that people don't accidentally use it, which is why I'm raising it here
• Some states award delegates at the statewide and congressional district levels - I wonder if it would be possible to take statewide CVRs that have the Congressional District noted as the precinct and run both statewide and precinct results (but treating precincts as individual contests, unlike current precinct counts in the Tabulator). happy to be shot down on this if it adds too much complexity to the tabulator.

Also attaching the delegate selection rules I've gotten so far. Hawaii, which won't be using the tabulator, hasn't yet sent me theirs. Kansas lays out their RCV rules on pages 3-5; Alaska on pages 6-7; and Wyoming on pages 8-9.
2020-Kansas-Delegate-Selection-Plan_122019.pdf
AK+DSP+12.20.19.pdf
WY Delegate Selection Plan Oct. 9.19.pdf

[tarheel]

OK, I had to refresh my memory on what "bottoms-up" means. According to our tabulator config documentation, setting winnerElectionMode to multiSeatBottomsUp means: "instead of running a standard multi-seat contest with single transferable votes, just eliminate candidates until there are numWinners remaining, then stop (only valid when numberOfWinners > 1)." But this isn't quite what we want here. We actually don't want to specify the number of seats at all, since the number of "winners" is just however many candidates are still active once we've managed to eliminate everyone who's below the threshold. (Regarding the question about whether the denominator is based on the first round or the current round: how will we get a clear answer on that? Basing it on the first round would feel more consistent with our existing logic, which defines the winning threshold for a multi-seat contest using the first round active vote count.)

My initial thought is that we should instead define a new option for winnerElectionMode called multiSeatBottomsUpWithThreshold, and a new field multiSeatBottomsUpThresholdValue that can be set to any number greater than 0 and less than or equal to 100 (not sure if it's OK to allow integers only). So you would enable this mode by using those two fields, and you would leave numberOfWinners blank in this case. That's going to be a bit gnarly on my end because the code currently assumes that numberOfWinners is always specified, but I think I can figure out a reasonable solution.

Regarding your question about selectively showing the threshold field: I wouldn't worry about that in the UI. We already have numerous config fields that are only valid when used in combination with certain other settings. We handle this by validating the config when you save or run it. In this case, for example, we would raise an error if you tried to set the threshold value without selecting multiSeatBottomsUpWithThreshold.

Regarding your question about Congressional districts: my instinct is that this would be adding a lot of complexity to the code to support a very niche use case. Would it be reasonable instead to expect the administrators to produce a separate CVR file for each district, and just run the contest once for each of these files?

Do I need to read through the attached rules, or can I assume that you'll alert us to any further details that are relevant to our coding work?

[chughes297]

Sorry, should have made that clearer - yes instead of a calculated seat-based threshold it's an arbitrary percentage threshold in this case.

Sounds good on the new winner election mode and threshold value field.

Makes sense on Congressional districts. I think yes, we should expect them to create a CVR for each district and work with it that way. I'll make sure my contact at Clear Ballot knows that, and just ensure that it's a sufficient solution for them.

No need to read through the rules, just wanted to be sure to share.

[tarheel]

Rob clarified to me that the denominator used to calculate the 15% threshold should be dynamic (based on active ballots in the current round).