Thursday, October 25, 2012

Data ambiguity and tolerance of errors

In the current election "season" in the USA there has been much ado about ensuring that only registered voters are allowed to vote. The Republican Party describes this as ensuring that any attempts at fraud are squelched. The Democratic Party describes this as being an attempt to reduce the likelihood that certain groups (largely Democrat voting) will vote. I certainly don't know which view is correct, and that is not the purpose of this post, but it does inform the thinking.

The "perfect" electoral system would ensure that everyone who has the right to vote can indeed do so, do so only once, and that no one who is not entitled to vote does not. Simple, eh? Not so much! Let me itemize some of the complexities that lead to data ambiguity.
  • Registration to vote has to be completed ahead of time (in many places).
  • The placement of a candidate on the ballot has to be done ahead of time, but write-in candidates are permissable under some circumstances..
  • Voters may vote ahead of time.
  • Voters vote in the precinct to which they are assigned (at least in some places)
  • Voters may mail in their votes (absentee ballots)
Again they don't appear insurmountable except that the time element causes some issues. Here are some to think about:
  • What if a person votes ahead of time, and then becomes "ineligible" prior to voting day. Possible causes include death, conviction of a felony, certifiably insane.
  • What if a person moves after registration, but before they vote?
  • What if a candidate becomes unfit after the ballots are printed and before early voting? (death, conviction of a felony, determination of status - eg not a natural born citizen
  • What if a candidate becomes unfit after early votes for that candidate have been cast?
  • .....
These are obviously just a few of the issues that might arise, but enough to give pause in thinking about the process. If we really want 100% accuracy we have a significant problem because we can't undo the history. Now if a voter has become ineligible after casting the vote (early voting or absentee ballot or before the closure of the polls if voting on election day), then how could the system determine that? It would be possible, to cross reference people who have voted with the death rolls (except of course if someone voted early so they could take their trip to look at the Angel Falls where they were killed by local tribespeople and no one knew until after the election).

On a more serious note, voting systems deliver inherently ambiguous results. Fortunately that ambiguity is tiny, but in ever closer elections, it gives those of us who think about systems somethings that are very hard to think about. That is, "How do we ensure the integrity of the total process?" and "How good is good enough?"

Actually that thinking should always apply. While we focus on the happy paths (the majority case), we should always be thinking about what the tolerance for error should be. It is, of course politcal suicide to say that there is error in the voting system, but rest assured - even without malice, there is plenty of opportunity for errors to creep in.


Richard Veryard said...

Clearly history matters. There are many possible sources of error and injustice in a voting system, but there are some specific tactics that have been used in the past to influence the result of an election, and these are the ones that the political parties tend to get most worked up about. Whereas most of the possible errors you identify would not obviously benefit one side more than the other.

However, there is a second-order problem. If there is a significant number of uncertain cases requiring some human judgement, then this introduces the possibility of a biased official exploiting the uncertainty to swing the election.

Fortunately, in a well-run democracy, you would never get the candidate's younger brother in a closely fought election controlling the administration of hanging chads. That would be like a referee in a soccer match sending off two members of the Chelsea team and ignoring the behaviour of the Manchester United team. Such things just couldn't happen, could they?

Chris Bird said...

Certainly Richard, there are egregious examples of people with an interest in the outcome making sure they influence the outcome. In the words (sort of) of Stalin and Beria. The outcome is not determined by the voters, but by those who count the votes.
In a children's book, I remember a character (a butcher) whose name was "thumb on the scales".
The bigger (from a systems persective) point is, I think, that we tend to view data at point in time, and whenever there are distributed systems, the time taken to synchronize state can always allow ambiguity to sneak in. If we are going to use eventually consistent models and the outcome depends on consistency, then we have to wait until "eventually" whenever that is