[EM] Clarifying the definitions

MIKE OSSIPOFF nkklrp at hotmail.com
Fri Jan 30 21:11:02 PST 2004


The sincerity definition wording at the website is:

>A sincere vote is one with no falsified preferences or preferences
>left unspecified when the election method allows them to be
>specified (in addition to the preferences already specified).

You said:

I'd read it, or rather mis-read it... then on second reading, I flat-out
mis-understood it.  It was the part about expressing preferences that
threw me, because my mindset at the time was that "preferring" a candidate
was the same thing as having that candidate "voted higher."
I wasn't thinking in terms of a preference being something in your head,
but rather something you marked on a ballot.  So my working definition of
"sincere vote" at the time went something like this:
"A sincere vote is one with no falsified preferences."

I reply:

Markus says that the academics use "preference" in the way that you 
interpreted it. But I believe that my meaning for it is in keeping with 
people's usage, and dictionaries, and that, if the academics mean 
"preference" as Markus says they do, then it is they who are changing its 
meaning.

Markus also said that the academics always define criteria in terms of 
actual votes, ballots, rather than mentioning "preference" in the usual 
sense of that word. Markus prefers that also. However, the fact that others 
only mention ballots doesn't mean that it's somehow improper to refer to 
preferences.

After all, if it weren't for preferences, there'd be no point in holding the 
election in the first place.

No one has given a reason why preferences shouldn't be mentioned in 
criteria. And the fact that Plurality meets CC when it's defined only in 
terms of ballots, suggests that definitions obeying that rule can't say what 
we expect CC to say. Unless one feels that Pluality meaningfully is a 
Condorcet Criterion method.

You continued:

Then, when I went back and re-read the definition, I didn't carry the "no"
through to apply to the latter half of the sentence, and so completely
misinterpreted its meaning.

I reply:

Sure, "or" probably should be replaced by "and no".

My own wording goes like this:

A voter votes sincerely if s/he doesn't falsify a preference or fail to vote 
a sincere preference that the balloting system in use would have allowed 
him/her to vote, in addition to the preferences that s/he actually did 
votre.

You continued:

And to be honest, I still have no idea
precisely what the parenthetical comment at the end is supposed to mean,
or why it's necessary.

I reply:

It's definitely necessary. Without it, no Approval ballot would be sincere, 
because, however you vote, you'd always be leaving un-voted one or more 
sincere preferences that Approval balloting would have allowed you to 
express.

For instance, say, with 4 candidates, you have preferences between every 
pair. You vote for A & B.

You haven't voted your preference for A over B, or for your preference for C 
over D. Approval would allow you to vorte those preference, since you could 
have voted only for A, thereby voting your preference for A over B. You 
could have voted your preference for C over D by voting  for A, B, & C.
So, when you vote for A & B, you've left unvoted some preferencs that 
Approval balloting would have allowed you to vote.

So that last phrase is essential. That part of the sincerity definition 
requires that you aren't leaving preferences for reasons other than the 
balloting system's limitations of your preference expression.
So, Approval doesn't pass SFC because sincere voting in Approval doesn't 
necessarily mean voting your preference for the CW over candidate B, as it 
does with rank balloting. Therefore, we can write an example of an Approval 
election in which a majority prefer the CW to B, and vote sincerely, with no 
one falsifying a preference, and B wins anyway.

Same with CC, as my Approval CC example shows.

Of course IRV has rank balloting and fails SFC anyway, as most rank methods 
do. And evenmost pairwise count methods fail SFC, GSFC, WDSC, & SDSC, even 
though the simple, modest Approval passes WDSC.

You continued:

.. and I also still think another "no" in front of
"preferences left unspecified" would help make it less ambiguous.)

I reply:

Yes, as I was saying above, "or" should be replaced by "and no". But of 
course I like my own wording best, as I quoted it above "...if s/he doesn't 
falsify a preference or fail to vote a sincere preference that the balloting 
system in use would have alloed him/her to vote in addition to the 
preferences that s/he actually did vote.

Mike Ossipoff

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