election-methods@mailman.electorama.com

Technical discussion of election methods

View all threads

Simple Tournament Proposal

FS
Forest Simmons
Wed, Mar 22, 2023 4:00 AM

Here's my suggestion for choice of tournament champion:

Lacking an undefeated team, elect the pairwise victor of the defensive and
offensive champs.

In the sports context the natural choices of offensive and defensive
champs, respectively are the team with the greatest point total, and the
team with the smallest opposing team points total, both totalled for the
entire tournament.

In the election context the natural choices of offensive and defensive
champs, respectively, are the candidate with the greatest vote total, and
the candidate with the smallest opposing vote total ... noth totalled for
all of the direct democratic matchups between pairs of candidates.

However, in the context of elections the presence of clone candidates will
unfairly distort these results. This distortion is easily overcome by the
following modification:

The Offensive Champ is the candidate that can honestly say "everybody else
had a matchup where they got fewer votes than I did in my worst matchup."

The Defensive Champ is the candidate that can honestly boast, "Every other
candidate had a matchup where their opponent got more votes than mine did
in my worst matchup."

How do we get the matchup votes for candidates X and Y in their direct
democratic compsrison?

They are simply the transferred votes that they would have if all of the
other candidates were eliminated.

Candidate X would get one vote from every ballot on which X is ranked ahead
of Y.

Similarly, Y's vote total in this contest is the number of ballots that
rank Y ahead of X.

Now, some technical notes for the election technicians ... everybody else
thanked with heartfelt appreciation for their participation ... and excused:

The Pairwise Support Matrix is the matrix whose entry PS(j, k) in column k
of row j ... is the number of ballots on which candidate j is ranked ahead
of candidate k.

In each row j, circle the smallest entry ... m(j) = min over k of PS(j,k).

In each column k, highlight its largest entry M(k) = Max over j of PS(j, k).

Let J be argMax m(j), obtained by looking at the row number of the largest
circled entry in the matrix.

Candidate J is the Offensive Champ.

Let K be argmin M(k), obtained by looking at the column number of the
smallest highlighted matrix entry.

Candidate K is the Defensive Champ.

If PS(J, K) is larger than
PO(J, K)=PS(K,J),  then candidate J, the Offensive Champ defeats the
Defensive Champ K.

If PS(J,K) is less than PO(J,K), then the Offensive Champ J is defeated by
the Defensive Champ K.

(Otherwise candidates J and K are tied)

-Forest

Here's my suggestion for choice of tournament champion: Lacking an undefeated team, elect the pairwise victor of the defensive and offensive champs. In the sports context the natural choices of offensive and defensive champs, respectively are the team with the greatest point total, and the team with the smallest opposing team points total, both totalled for the entire tournament. In the election context the natural choices of offensive and defensive champs, respectively, are the candidate with the greatest vote total, and the candidate with the smallest opposing vote total ... noth totalled for all of the direct democratic matchups between pairs of candidates. However, in the context of elections the presence of clone candidates will unfairly distort these results. This distortion is easily overcome by the following modification: The Offensive Champ is the candidate that can honestly say "everybody else had a matchup where they got fewer votes than I did in my worst matchup." The Defensive Champ is the candidate that can honestly boast, "Every other candidate had a matchup where their opponent got more votes than mine did in my worst matchup." How do we get the matchup votes for candidates X and Y in their direct democratic compsrison? They are simply the transferred votes that they would have if all of the other candidates were eliminated. Candidate X would get one vote from every ballot on which X is ranked ahead of Y. Similarly, Y's vote total in this contest is the number of ballots that rank Y ahead of X. Now, some technical notes for the election technicians ... everybody else thanked with heartfelt appreciation for their participation ... and excused: The Pairwise Support Matrix is the matrix whose entry PS(j, k) in column k of row j ... is the number of ballots on which candidate j is ranked ahead of candidate k. In each row j, circle the smallest entry ... m(j) = min over k of PS(j,k). In each column k, highlight its largest entry M(k) = Max over j of PS(j, k). Let J be argMax m(j), obtained by looking at the row number of the largest circled entry in the matrix. Candidate J is the Offensive Champ. Let K be argmin M(k), obtained by looking at the column number of the smallest highlighted matrix entry. Candidate K is the Defensive Champ. If PS(J, K) is larger than PO(J, K)=PS(K,J), then candidate J, the Offensive Champ defeats the Defensive Champ K. If PS(J,K) is less than PO(J,K), then the Offensive Champ J is defeated by the Defensive Champ K. (Otherwise candidates J and K are tied) -Forest
RL
Richard Lung
Wed, Mar 22, 2023 7:09 AM

The superiority of sport to politics is that sports have independent
referees. Referees have rules of independence unlike many referendums.
In the US city referendums, the Machine, such as Tammany Hall in New
York and about 20 American cities used referendums as battering rams to
reinstate monopolistic elections against proportional representation
with a single transferable vote. Likewise Britain has no referendum
rules and is fine with money and publicity deciding the issue.

Paddy Ashdown, former Liberal Democrat leader, said of the 2011
Alternative Vote referendum: "They marshalled a regiment of lies." And
IRV is still monopolistic, despite the ranked choice vote. It's a basc
principle of scientific investigation not to prejudge what one is
supposed to prove. A representative sample of self-informing public
opinion, a Citizens Assembly, can be a referee. As it was in British
Columbia, with independence rules, before the politicians lost
self-restraint and rigged the referendum rules, with a one and a half
votes weighting in favor of FPTP (double 60% thresholds).

The relevance of all this, in case you're wondering, is that there is no
authoritative "standard model" of elections, as there is a standard
model in physics, despite its acknowledged imperfections. Therefore, it
follows that election implementation is not the decision of experts, as
it would be, regarding phyics or biology, for instance, but has to have
the crude fall-back of referee devices like a Citizens Assembly, which
reformers in Canada widely seem to recognise.

Regards,

Richard Lung.

On 22/03/2023 04:00, Forest Simmons wrote:

Here's my suggestion for choice of tournament champion:

Lacking an undefeated team, elect the pairwise victor of the defensive
and offensive champs.

In the sports context the natural choices of offensive and defensive
champs, respectively are the team with the greatest point total, and
the team with the smallest opposing team points total, both totalled
for the entire tournament.

In the election context the natural choices of offensive and defensive
champs, respectively, are the candidate with the greatest vote total,
and the candidate with the smallest opposing vote total ... noth
totalled for all of the direct democratic matchups between pairs of
candidates.

However, in the context of elections the presence of clone candidates
will unfairly distort these results. This distortion is easily
overcome by the following modification:

The Offensive Champ is the candidate that can honestly say "everybody
else had a matchup where they got fewer votes than I did in my worst
matchup."

The Defensive Champ is the candidate that can honestly boast, "Every
other candidate had a matchup where their opponent got more votes than
mine did in my worst matchup."

How do we get the matchup votes for candidates X and Y in their direct
democratic compsrison?

They are simply the transferred votes that they would have if all of
the other candidates were eliminated.

Candidate X would get one vote from every ballot on which X is ranked
ahead of Y.

Similarly, Y's vote total in this contest is the number of ballots
that rank Y ahead of X.

Now, some technical notes for the election technicians ... everybody
else thanked with heartfelt appreciation for their participation ...
and excused:

The Pairwise Support Matrix is the matrix whose entry PS(j, k) in
column k of row j ... is the number of ballots on which candidate j is
ranked ahead of candidate k.

In each row j, circle the smallest entry ... m(j) = min over k of PS(j,k).

In each column k, highlight its largest entry M(k) = Max over j of
PS(j, k).

Let J be argMax m(j), obtained by looking at the row number of the
largest circled entry in the matrix.

Candidate J is the Offensive Champ.

Let K be argmin M(k), obtained by looking at the column number of the
smallest highlighted matrix entry.

Candidate K is the Defensive Champ.

If PS(J, K) is larger than
PO(J, K)=PS(K,J),  then candidate J, the Offensive Champ defeats the
Defensive Champ K.

If PS(J,K) is less than PO(J,K), then the Offensive Champ J is
defeated by the Defensive Champ K.

(Otherwise candidates J and K are tied)

-Forest


Election-Methods mailing list - seehttps://electorama.com/em  for list info

The superiority of sport to politics is that sports have independent referees. Referees have rules of independence unlike many referendums. In the US city referendums, the Machine, such as Tammany Hall in New York and about 20 American cities used referendums as battering rams to reinstate monopolistic elections against proportional representation with a single transferable vote. Likewise Britain has no referendum rules and is fine with money and publicity deciding the issue. Paddy Ashdown, former Liberal Democrat leader, said of the 2011 Alternative Vote referendum: "They marshalled a regiment of lies." And IRV is still monopolistic, despite the ranked choice vote. It's a basc principle of scientific investigation not to prejudge what one is supposed to prove. A representative sample of self-informing public opinion, a Citizens Assembly, can be a referee. As it was in British Columbia, with independence rules, before the politicians lost self-restraint and rigged the referendum rules, with a one and a half votes weighting in favor of FPTP (double 60% thresholds). The relevance of all this, in case you're wondering, is that there is no authoritative "standard model" of elections, as there is a standard model in physics, despite its acknowledged imperfections. Therefore, it follows that election implementation is not the decision of experts, as it would be, regarding phyics or biology, for instance, but has to have the crude fall-back of referee devices like a Citizens Assembly, which reformers in Canada widely seem to recognise. Regards, Richard Lung. On 22/03/2023 04:00, Forest Simmons wrote: > Here's my suggestion for choice of tournament champion: > > Lacking an undefeated team, elect the pairwise victor of the defensive > and offensive champs. > > In the sports context the natural choices of offensive and defensive > champs, respectively are the team with the greatest point total, and > the team with the smallest opposing team points total, both totalled > for the entire tournament. > > In the election context the natural choices of offensive and defensive > champs, respectively, are the candidate with the greatest vote total, > and the candidate with the smallest opposing vote total ... noth > totalled for all of the direct democratic matchups between pairs of > candidates. > > However, in the context of elections the presence of clone candidates > will unfairly distort these results. This distortion is easily > overcome by the following modification: > > The Offensive Champ is the candidate that can honestly say "everybody > else had a matchup where they got fewer votes than I did in my worst > matchup." > > The Defensive Champ is the candidate that can honestly boast, "Every > other candidate had a matchup where their opponent got more votes than > mine did in my worst matchup." > > How do we get the matchup votes for candidates X and Y in their direct > democratic compsrison? > > They are simply the transferred votes that they would have if all of > the other candidates were eliminated. > > Candidate X would get one vote from every ballot on which X is ranked > ahead of Y. > > Similarly, Y's vote total in this contest is the number of ballots > that rank Y ahead of X. > > Now, some technical notes for the election technicians ... everybody > else thanked with heartfelt appreciation for their participation ... > and excused: > > The Pairwise Support Matrix is the matrix whose entry PS(j, k) in > column k of row j ... is the number of ballots on which candidate j is > ranked ahead of candidate k. > > In each row j, circle the smallest entry ... m(j) = min over k of PS(j,k). > > In each column k, highlight its largest entry M(k) = Max over j of > PS(j, k). > > Let J be argMax m(j), obtained by looking at the row number of the > largest circled entry in the matrix. > > Candidate J is the Offensive Champ. > > Let K be argmin M(k), obtained by looking at the column number of the > smallest highlighted matrix entry. > > Candidate K is the Defensive Champ. > > If PS(J, K) is larger than > PO(J, K)=PS(K,J),  then candidate J, the Offensive Champ defeats the > Defensive Champ K. > > If PS(J,K) is less than PO(J,K), then the Offensive Champ J is > defeated by the Defensive Champ K. > > (Otherwise candidates J and K are tied) > > -Forest > > ---- > Election-Methods mailing list - seehttps://electorama.com/em for list info
FS
Forest Simmons
Wed, Mar 22, 2023 12:31 PM

Time for an example or two.

48 C
28 A>B
24 B

A>B 28 to 24
B>C 52 to 48
C>A 48 to 28

The respective minPS scores are their Top counts 28, 24, &48
So C is the offensive champ with MaxminPS(C)=48.

MaxPO(C)=52 (from B)

A and B are tied for minMaxPO at 48 from C. This tie is broken by looking
at the other PO scores 24 and 28, respectively. So A is the minMaxPO
candidate (defensive champ) with MaxPO(A)=48+24epsilon, ehich is less than
MaxPO(B)=48+28epsilon, and (as already noted) less than MaxPO(C)=52.

Since the Offensive Champ C beats the Defensive Champ A, (48 to 28) and
there is no undefeated candidate, our tournament method elects C.

Now let's look at ...

a A>B(sincere A>C)
b B>C
c C>A

If the A faction is largest its burial of the sincere CW C pays., but the
because A is both the Offensive Champ and the Defensive Champ with
minPS(A)=a.

But suppose C takes the customary sincere CW precaution of bullet voting:

a A>B
b B>C
c C

Then the respective minPS scores are a, b, and c.

Continuing our assumption that enabled the A faction to bury C with
impunity ... namely a>max(b,c), we see that A retains its status as
Offensive Champ with minPS(A)=a>max(b,c).

The MaxPO's are now ...
(b+c)=MaxPO(A), a=MaxPO(B), and (a+b)=MaxPO(C).

The min of these is a=MaxPO(B). So B is the Defensive Champ.

The pairwise contest between the two champs is A vs B ... which still lets
the A faction get away with its burial of the sincere CW.

We see that under this method the sincere CW is at the mercy of the largest
faction.

So despite the nice sports tournament heuristic... we cannot endorse this
method!

It's a good thing we have better methods that are conceptually and
operationally just as simple ... if not as innately appealing to sports
enthusiasts.

Is there a better pair of fall back candidates to choose between when there
is no ballot CW?

How about the implicit approval candidate versus the Max Equal Top
candidate?

The beauty of this class of methods is only one pass through the ballots,
as long as the two contenders are kept simple enough.

-Forest

On Tue, Mar 21, 2023, 9:00 PM Forest Simmons forest.simmons21@gmail.com
wrote:

Here's my suggestion for choice of tournament champion:

Lacking an undefeated team, elect the pairwise victor of the defensive and
offensive champs.

In the sports context the natural choices of offensive and defensive
champs, respectively are the team with the greatest point total, and the
team with the smallest opposing team points total, both totalled for the
entire tournament.

In the election context the natural choices of offensive and defensive
champs, respectively, are the candidate with the greatest vote total, and
the candidate with the smallest opposing vote total ... noth totalled for
all of the direct democratic matchups between pairs of candidates.

However, in the context of elections the presence of clone candidates will
unfairly distort these results. This distortion is easily overcome by the
following modification:

The Offensive Champ is the candidate that can honestly say "everybody else
had a matchup where they got fewer votes than I did in my worst matchup."

The Defensive Champ is the candidate that can honestly boast, "Every other
candidate had a matchup where their opponent got more votes than mine did
in my worst matchup."

How do we get the matchup votes for candidates X and Y in their direct
democratic compsrison?

They are simply the transferred votes that they would have if all of the
other candidates were eliminated.

Candidate X would get one vote from every ballot on which X is ranked
ahead of Y.

Similarly, Y's vote total in this contest is the number of ballots that
rank Y ahead of X.

Now, some technical notes for the election technicians ... everybody else
thanked with heartfelt appreciation for their participation ... and excused:

The Pairwise Support Matrix is the matrix whose entry PS(j, k) in column k
of row j ... is the number of ballots on which candidate j is ranked ahead
of candidate k.

In each row j, circle the smallest entry ... m(j) = min over k of PS(j,k).

In each column k, highlight its largest entry M(k) = Max over j of PS(j,
k).

Let J be argMax m(j), obtained by looking at the row number of the largest
circled entry in the matrix.

Candidate J is the Offensive Champ.

Let K be argmin M(k), obtained by looking at the column number of the
smallest highlighted matrix entry.

Candidate K is the Defensive Champ.

If PS(J, K) is larger than
PO(J, K)=PS(K,J),  then candidate J, the Offensive Champ defeats the
Defensive Champ K.

If PS(J,K) is less than PO(J,K), then the Offensive Champ J is defeated by
the Defensive Champ K.

(Otherwise candidates J and K are tied)

-Forest

Time for an example or two. 48 C 28 A>B 24 B A>B 28 to 24 B>C 52 to 48 C>A 48 to 28 The respective minPS scores are their Top counts 28, 24, &48 So C is the offensive champ with MaxminPS(C)=48. MaxPO(C)=52 (from B) A and B are tied for minMaxPO at 48 from C. This tie is broken by looking at the other PO scores 24 and 28, respectively. So A is the minMaxPO candidate (defensive champ) with MaxPO(A)=48+24epsilon, ehich is less than MaxPO(B)=48+28epsilon, and (as already noted) less than MaxPO(C)=52. Since the Offensive Champ C beats the Defensive Champ A, (48 to 28) and there is no undefeated candidate, our tournament method elects C. Now let's look at ... a A>B(sincere A>C) b B>C c C>A If the A faction is largest its burial of the sincere CW C pays., but the because A is both the Offensive Champ and the Defensive Champ with minPS(A)=a. But suppose C takes the customary sincere CW precaution of bullet voting: a A>B b B>C c C Then the respective minPS scores are a, b, and c. Continuing our assumption that enabled the A faction to bury C with impunity ... namely a>max(b,c), we see that A retains its status as Offensive Champ with minPS(A)=a>max(b,c). The MaxPO's are now ... (b+c)=MaxPO(A), a=MaxPO(B), and (a+b)=MaxPO(C). The min of these is a=MaxPO(B). So B is the Defensive Champ. The pairwise contest between the two champs is A vs B ... which still lets the A faction get away with its burial of the sincere CW. We see that under this method the sincere CW is at the mercy of the largest faction. So despite the nice sports tournament heuristic... we cannot endorse this method! It's a good thing we have better methods that are conceptually and operationally just as simple ... if not as innately appealing to sports enthusiasts. Is there a better pair of fall back candidates to choose between when there is no ballot CW? How about the implicit approval candidate versus the Max Equal Top candidate? The beauty of this class of methods is only one pass through the ballots, as long as the two contenders are kept simple enough. -Forest On Tue, Mar 21, 2023, 9:00 PM Forest Simmons <forest.simmons21@gmail.com> wrote: > Here's my suggestion for choice of tournament champion: > > Lacking an undefeated team, elect the pairwise victor of the defensive and > offensive champs. > > In the sports context the natural choices of offensive and defensive > champs, respectively are the team with the greatest point total, and the > team with the smallest opposing team points total, both totalled for the > entire tournament. > > In the election context the natural choices of offensive and defensive > champs, respectively, are the candidate with the greatest vote total, and > the candidate with the smallest opposing vote total ... noth totalled for > all of the direct democratic matchups between pairs of candidates. > > However, in the context of elections the presence of clone candidates will > unfairly distort these results. This distortion is easily overcome by the > following modification: > > The Offensive Champ is the candidate that can honestly say "everybody else > had a matchup where they got fewer votes than I did in my worst matchup." > > The Defensive Champ is the candidate that can honestly boast, "Every other > candidate had a matchup where their opponent got more votes than mine did > in my worst matchup." > > How do we get the matchup votes for candidates X and Y in their direct > democratic compsrison? > > They are simply the transferred votes that they would have if all of the > other candidates were eliminated. > > Candidate X would get one vote from every ballot on which X is ranked > ahead of Y. > > Similarly, Y's vote total in this contest is the number of ballots that > rank Y ahead of X. > > Now, some technical notes for the election technicians ... everybody else > thanked with heartfelt appreciation for their participation ... and excused: > > The Pairwise Support Matrix is the matrix whose entry PS(j, k) in column k > of row j ... is the number of ballots on which candidate j is ranked ahead > of candidate k. > > In each row j, circle the smallest entry ... m(j) = min over k of PS(j,k). > > In each column k, highlight its largest entry M(k) = Max over j of PS(j, > k). > > Let J be argMax m(j), obtained by looking at the row number of the largest > circled entry in the matrix. > > Candidate J is the Offensive Champ. > > Let K be argmin M(k), obtained by looking at the column number of the > smallest highlighted matrix entry. > > Candidate K is the Defensive Champ. > > If PS(J, K) is larger than > PO(J, K)=PS(K,J), then candidate J, the Offensive Champ defeats the > Defensive Champ K. > > If PS(J,K) is less than PO(J,K), then the Offensive Champ J is defeated by > the Defensive Champ K. > > (Otherwise candidates J and K are tied) > > -Forest >
KM
Kristofer Munsterhjelm
Wed, Mar 22, 2023 1:03 PM

On 3/22/23 05:00, Forest Simmons wrote:

Here's my suggestion for choice of tournament champion:

Lacking an undefeated team, elect the pairwise victor of the defensive
and offensive champs.

I'll have to investigate further, but my impression from working with
burial-resistant methods is that it's impossible to make a method that's
burial resistant (in the DMTCBR sense) without using positional data.

However, another important property to note is that the modes of
strategy very much depend on how the data is gathered. In an election
situation, burial is fairly easy: just change A>X>B>C>D>E>F into
A>B>C>D>E>F>X. But in sports, the analog would be that A decides to tell
B to "strategically defeat X", e.g. to score more goals against X (or
similar) to push X further down the ranking. Presumably any team B would
be doing its best to defeat X already, so "burial" doesn't really seem
to be a strategy in sports.

Thus it's not a problem that we don't have positional data, because we
don't need to defend against that particular strategy.

In sports, what strategies could exist? I'd imagine something more
like... team B tells team X to play badly against team C, because the
tiebreaker won't make X win anyway. Thus if say, the Smith set is ABCX,
then it's possible that X losing more heavily against C could make B win
instead of A. That's more like compromising, but it's not quite the same
thing.

-km

On 3/22/23 05:00, Forest Simmons wrote: > Here's my suggestion for choice of tournament champion: > > Lacking an undefeated team, elect the pairwise victor of the defensive > and offensive champs. I'll have to investigate further, but my impression from working with burial-resistant methods is that it's impossible to make a method that's burial resistant (in the DMTCBR sense) without using positional data. However, another important property to note is that the modes of strategy very much depend on how the data is gathered. In an election situation, burial is fairly easy: just change A>X>B>C>D>E>F into A>B>C>D>E>F>X. But in sports, the analog would be that A decides to tell B to "strategically defeat X", e.g. to score more goals against X (or similar) to push X further down the ranking. Presumably any team B would be doing its best to defeat X already, so "burial" doesn't really seem to be a strategy in sports. Thus it's not a problem that we don't have positional data, because we don't need to defend against that particular strategy. In sports, what strategies could exist? I'd imagine something more like... team B tells team X to play badly against team C, because the tiebreaker won't make X win anyway. Thus if say, the Smith set is ABCX, then it's possible that X losing more heavily against C could make B win instead of A. That's more like compromising, but it's not quite the same thing. -km
HP
Hahn, Paul
Wed, Mar 22, 2023 2:24 PM

"In sports, what strategies could exist? I'd imagine something more like... team B tells team X to play badly against team C, because the tiebreaker won't make X win anyway. Thus if say, the Smith set is ABCX, then it's possible that X losing more heavily against C could make B win instead of A. That's more like compromising, but it's not quite the same thing."

AFAIK the majority of deliberate losing (or not winning as handily as one is capable) in sports are to take advantage of side bets.  I can imagine that in a double elimination tournament one might deliberately go over to the loser's bracket to avoid a team one is particularly bad against, in the hope that they'll be eliminated before you have to face them.  But that means you have to fight your way through the loser's bracket, which means more matches; I don't know that it would be worth it most of the time.

The other scenario I am aware of is that in chess and some other sports, one can lose or not win as big to avoid having your rating increased, so that (again) you get to face lesser opposition.  This definitely happens.

I'm not sure how much of this carries over to an election situation, though.

--pH

-----Original Message-----
From: Election-Methods election-methods-bounces@lists.electorama.com On Behalf Of Kristofer Munsterhjelm
Sent: Wednesday, March 22, 2023 8:03 AM
To: Forest Simmons forest.simmons21@gmail.com; EM Election-methods@lists.electorama.com; Kevin Venzke stepjak@yahoo.fr; Andy Jennings elections@jenningsstory.com; Colin Champion colin.champion@routemaster.app; Andy Dienes andydienes@gmail.com
Subject: Re: [EM] Simple Tournament Proposal

On 3/22/23 05:00, Forest Simmons wrote:

Here's my suggestion for choice of tournament champion:

Lacking an undefeated team, elect the pairwise victor of the defensive
and offensive champs.

I'll have to investigate further, but my impression from working with burial-resistant methods is that it's impossible to make a method that's burial resistant (in the DMTCBR sense) without using positional data.

However, another important property to note is that the modes of strategy very much depend on how the data is gathered. In an election situation, burial is fairly easy: just change A>X>B>C>D>E>F into
A>B>C>D>E>F>X. But in sports, the analog would be that A decides to tell
B to "strategically defeat X", e.g. to score more goals against X (or
similar) to push X further down the ranking. Presumably any team B would be doing its best to defeat X already, so "burial" doesn't really seem to be a strategy in sports.

Thus it's not a problem that we don't have positional data, because we don't need to defend against that particular strategy.

In sports, what strategies could exist? I'd imagine something more like... team B tells team X to play badly against team C, because the tiebreaker won't make X win anyway. Thus if say, the Smith set is ABCX, then it's possible that X losing more heavily against C could make B win instead of A. That's more like compromising, but it's not quite the same thing.

-km

Election-Methods mailing list - see https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Felectorama.com%2Fem&data=05%7C01%7Cmanynote%40wustl.edu%7Cee6ae3e76d5743655c5008db2ad5e2b3%7C4ccca3b571cd4e6d974b4d9beb96c6d6%7C0%7C0%7C638150870360304884%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=hv3F8bg%2BjtQKHlWpl4fI2S2GtlX%2FdMb1KFY%2BgGrTN0o%3D&reserved=0 for list info

"In sports, what strategies could exist? I'd imagine something more like... team B tells team X to play badly against team C, because the tiebreaker won't make X win anyway. Thus if say, the Smith set is ABCX, then it's possible that X losing more heavily against C could make B win instead of A. That's more like compromising, but it's not quite the same thing." AFAIK the majority of deliberate losing (or not winning as handily as one is capable) in sports are to take advantage of side bets. I can imagine that in a double elimination tournament one might deliberately go over to the loser's bracket to avoid a team one is particularly bad against, in the hope that they'll be eliminated before you have to face them. But that means you have to fight your way through the loser's bracket, which means more matches; I don't know that it would be worth it most of the time. The other scenario I am aware of is that in chess and some other sports, one can lose or not win as big to avoid having your rating increased, so that (again) you get to face lesser opposition. This definitely happens. I'm not sure how much of this carries over to an election situation, though. --pH -----Original Message----- From: Election-Methods <election-methods-bounces@lists.electorama.com> On Behalf Of Kristofer Munsterhjelm Sent: Wednesday, March 22, 2023 8:03 AM To: Forest Simmons <forest.simmons21@gmail.com>; EM <Election-methods@lists.electorama.com>; Kevin Venzke <stepjak@yahoo.fr>; Andy Jennings <elections@jenningsstory.com>; Colin Champion <colin.champion@routemaster.app>; Andy Dienes <andydienes@gmail.com> Subject: Re: [EM] Simple Tournament Proposal On 3/22/23 05:00, Forest Simmons wrote: > Here's my suggestion for choice of tournament champion: > > Lacking an undefeated team, elect the pairwise victor of the defensive > and offensive champs. I'll have to investigate further, but my impression from working with burial-resistant methods is that it's impossible to make a method that's burial resistant (in the DMTCBR sense) without using positional data. However, another important property to note is that the modes of strategy very much depend on how the data is gathered. In an election situation, burial is fairly easy: just change A>X>B>C>D>E>F into A>B>C>D>E>F>X. But in sports, the analog would be that A decides to tell B to "strategically defeat X", e.g. to score more goals against X (or similar) to push X further down the ranking. Presumably any team B would be doing its best to defeat X already, so "burial" doesn't really seem to be a strategy in sports. Thus it's not a problem that we don't have positional data, because we don't need to defend against that particular strategy. In sports, what strategies could exist? I'd imagine something more like... team B tells team X to play badly against team C, because the tiebreaker won't make X win anyway. Thus if say, the Smith set is ABCX, then it's possible that X losing more heavily against C could make B win instead of A. That's more like compromising, but it's not quite the same thing. -km ---- Election-Methods mailing list - see https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Felectorama.com%2Fem&data=05%7C01%7Cmanynote%40wustl.edu%7Cee6ae3e76d5743655c5008db2ad5e2b3%7C4ccca3b571cd4e6d974b4d9beb96c6d6%7C0%7C0%7C638150870360304884%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=hv3F8bg%2BjtQKHlWpl4fI2S2GtlX%2FdMb1KFY%2BgGrTN0o%3D&reserved=0 for list info
FS
Forest Simmons
Wed, Mar 22, 2023 5:48 PM

All of this groping for a halfway decent Quick & Clean tournament method
has brought me to this:

Lacking an undefeated candidate, elect the candidate who defeats the
Defensive Champ with the most winning votes.

To define the Defensive Champ, we need to know for each pair of candidates
X and Y the number of ballots on which Y was ranked ahead of X ... this is
the Pairwise Opposition of Y against X, denoted PO(Y,X)

The MaxPO of X or MPO(X) is the greatest value of PO(Y,X) as Y ranges over
all of X's opponents. This MPO(X) is X's defensive score ... the smaller
the better ... it is the most "points" (votes) any opponent of X has made
against X in any pairwise matchup of this election.

The Defensive Champ is argminMPO(X), the candidate whose MPO value is
smaller than any other candidates MPO value.

So the Defensive Champ is the one who "lets slip" the fewest votes to any
of her opponents ... almost as if she had some psychic power to keep votes
against her from reaching the ballot box.

So this Defensive Champ is a strong candidate ... but the candidate that
overcomes that strong resistance and gets the most votes past her defense
is even stronger ... and that's the one our method chooses!

Example:

a A>B (Sincere A>C)
b B>C
c C>A

The MPO's of the respective candidates are MPO(A)=(n-a), MPO(B)=(n-b), and
MPO(C)=(n-c). So the Defensive Champ is A, assuming the A faction is
largest (emboldening the burial).

The winner is supposed to be the candidate with the strongest defeat
against the Defensive Champ A. So C is the only candidate that qualifies,
since no other candidate defeats A.

So we see that the sincere CW is restored.

Example 2.

48 C
28 A>B
24 B(Sincere B>A)

In a previous message we found that the Defensive Champ was A, who is
defeated only by C ... therefore the winner.

So the B faction's defection backfired.

So far, so good ... not at all surprising ... because I had these examples
in mind when I designed this method;-)

We need somebody to run some tests.

-Forest

On Wed, Mar 22, 2023, 7:31 AM Hahn, Paul manynote@wustl.edu wrote:

"In sports, what strategies could exist? I'd imagine something more
like... team B tells team X to play badly against team C, because the
tiebreaker won't make X win anyway. Thus if say, the Smith set is ABCX,
then it's possible that X losing more heavily against C could make B win
instead of A. That's more like compromising, but it's not quite the same
thing."

AFAIK the majority of deliberate losing (or not winning as handily as one
is capable) in sports are to take advantage of side bets.  I can imagine
that in a double elimination tournament one might deliberately go over to
the loser's bracket to avoid a team one is particularly bad against, in the
hope that they'll be eliminated before you have to face them.  But that
means you have to fight your way through the loser's bracket, which means
more matches; I don't know that it would be worth it most of the time.

The other scenario I am aware of is that in chess and some other sports,
one can lose or not win as big to avoid having your rating increased, so
that (again) you get to face lesser opposition.  This definitely happens.

I'm not sure how much of this carries over to an election situation,
though.

--pH

-----Original Message-----
From: Election-Methods election-methods-bounces@lists.electorama.com On
Behalf Of Kristofer Munsterhjelm
Sent: Wednesday, March 22, 2023 8:03 AM
To: Forest Simmons forest.simmons21@gmail.com; EM <
Election-methods@lists.electorama.com>; Kevin Venzke stepjak@yahoo.fr;
Andy Jennings elections@jenningsstory.com; Colin Champion <
colin.champion@routemaster.app>; Andy Dienes andydienes@gmail.com
Subject: Re: [EM] Simple Tournament Proposal

On 3/22/23 05:00, Forest Simmons wrote:

Here's my suggestion for choice of tournament champion:

Lacking an undefeated team, elect the pairwise victor of the defensive
and offensive champs.

I'll have to investigate further, but my impression from working with
burial-resistant methods is that it's impossible to make a method that's
burial resistant (in the DMTCBR sense) without using positional data.

However, another important property to note is that the modes of strategy
very much depend on how the data is gathered. In an election situation,
burial is fairly easy: just change A>X>B>C>D>E>F into
A>B>C>D>E>F>X. But in sports, the analog would be that A decides to tell
B to "strategically defeat X", e.g. to score more goals against X (or
similar) to push X further down the ranking. Presumably any team B would
be doing its best to defeat X already, so "burial" doesn't really seem to
be a strategy in sports.

Thus it's not a problem that we don't have positional data, because we
don't need to defend against that particular strategy.

In sports, what strategies could exist? I'd imagine something more like...
team B tells team X to play badly against team C, because the tiebreaker
won't make X win anyway. Thus if say, the Smith set is ABCX, then it's
possible that X losing more heavily against C could make B win instead of
A. That's more like compromising, but it's not quite the same thing.

-km

Election-Methods mailing list - see
https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Felectorama.com%2Fem&data=05%7C01%7Cmanynote%40wustl.edu%7Cee6ae3e76d5743655c5008db2ad5e2b3%7C4ccca3b571cd4e6d974b4d9beb96c6d6%7C0%7C0%7C638150870360304884%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=hv3F8bg%2BjtQKHlWpl4fI2S2GtlX%2FdMb1KFY%2BgGrTN0o%3D&reserved=0
for list info

Election-Methods mailing list - see https://electorama.com/em for list
info

All of this groping for a halfway decent Quick & Clean tournament method has brought me to this: Lacking an undefeated candidate, elect the candidate who defeats the Defensive Champ with the most winning votes. To define the Defensive Champ, we need to know for each pair of candidates X and Y the number of ballots on which Y was ranked ahead of X ... this is the Pairwise Opposition of Y against X, denoted PO(Y,X) The MaxPO of X or MPO(X) is the greatest value of PO(Y,X) as Y ranges over all of X's opponents. This MPO(X) is X's defensive score ... the smaller the better ... it is the most "points" (votes) any opponent of X has made against X in any pairwise matchup of this election. The Defensive Champ is argminMPO(X), the candidate whose MPO value is smaller than any other candidates MPO value. So the Defensive Champ is the one who "lets slip" the fewest votes to any of her opponents ... almost as if she had some psychic power to keep votes against her from reaching the ballot box. So this Defensive Champ is a strong candidate ... but the candidate that overcomes that strong resistance and gets the most votes past her defense is even stronger ... and that's the one our method chooses! Example: a A>B (Sincere A>C) b B>C c C>A The MPO's of the respective candidates are MPO(A)=(n-a), MPO(B)=(n-b), and MPO(C)=(n-c). So the Defensive Champ is A, assuming the A faction is largest (emboldening the burial). The winner is supposed to be the candidate with the strongest defeat against the Defensive Champ A. So C is the only candidate that qualifies, since no other candidate defeats A. So we see that the sincere CW is restored. Example 2. 48 C 28 A>B 24 B(Sincere B>A) In a previous message we found that the Defensive Champ was A, who is defeated only by C ... therefore the winner. So the B faction's defection backfired. So far, so good ... not at all surprising ... because I had these examples in mind when I designed this method;-) We need somebody to run some tests. -Forest On Wed, Mar 22, 2023, 7:31 AM Hahn, Paul <manynote@wustl.edu> wrote: > "In sports, what strategies could exist? I'd imagine something more > like... team B tells team X to play badly against team C, because the > tiebreaker won't make X win anyway. Thus if say, the Smith set is ABCX, > then it's possible that X losing more heavily against C could make B win > instead of A. That's more like compromising, but it's not quite the same > thing." > > AFAIK the majority of deliberate losing (or not winning as handily as one > is capable) in sports are to take advantage of side bets. I can imagine > that in a double elimination tournament one might deliberately go over to > the loser's bracket to avoid a team one is particularly bad against, in the > hope that they'll be eliminated before you have to face them. But that > means you have to fight your way through the loser's bracket, which means > more matches; I don't know that it would be worth it most of the time. > > The other scenario I am aware of is that in chess and some other sports, > one can lose or not win as big to avoid having your rating increased, so > that (again) you get to face lesser opposition. This definitely happens. > > I'm not sure how much of this carries over to an election situation, > though. > > --pH > > -----Original Message----- > From: Election-Methods <election-methods-bounces@lists.electorama.com> On > Behalf Of Kristofer Munsterhjelm > Sent: Wednesday, March 22, 2023 8:03 AM > To: Forest Simmons <forest.simmons21@gmail.com>; EM < > Election-methods@lists.electorama.com>; Kevin Venzke <stepjak@yahoo.fr>; > Andy Jennings <elections@jenningsstory.com>; Colin Champion < > colin.champion@routemaster.app>; Andy Dienes <andydienes@gmail.com> > Subject: Re: [EM] Simple Tournament Proposal > > On 3/22/23 05:00, Forest Simmons wrote: > > Here's my suggestion for choice of tournament champion: > > > > Lacking an undefeated team, elect the pairwise victor of the defensive > > and offensive champs. > > I'll have to investigate further, but my impression from working with > burial-resistant methods is that it's impossible to make a method that's > burial resistant (in the DMTCBR sense) without using positional data. > > However, another important property to note is that the modes of strategy > very much depend on how the data is gathered. In an election situation, > burial is fairly easy: just change A>X>B>C>D>E>F into > A>B>C>D>E>F>X. But in sports, the analog would be that A decides to tell > B to "strategically defeat X", e.g. to score more goals against X (or > similar) to push X further down the ranking. Presumably any team B would > be doing its best to defeat X already, so "burial" doesn't really seem to > be a strategy in sports. > > Thus it's not a problem that we don't have positional data, because we > don't need to defend against that particular strategy. > > In sports, what strategies could exist? I'd imagine something more like... > team B tells team X to play badly against team C, because the tiebreaker > won't make X win anyway. Thus if say, the Smith set is ABCX, then it's > possible that X losing more heavily against C could make B win instead of > A. That's more like compromising, but it's not quite the same thing. > > -km > ---- > Election-Methods mailing list - see > https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Felectorama.com%2Fem&data=05%7C01%7Cmanynote%40wustl.edu%7Cee6ae3e76d5743655c5008db2ad5e2b3%7C4ccca3b571cd4e6d974b4d9beb96c6d6%7C0%7C0%7C638150870360304884%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=hv3F8bg%2BjtQKHlWpl4fI2S2GtlX%2FdMb1KFY%2BgGrTN0o%3D&reserved=0 > for list info > ---- > Election-Methods mailing list - see https://electorama.com/em for list > info >
FS
Forest Simmons
Wed, Mar 22, 2023 5:54 PM

Is clone dependence a problem ... teaming or crowding in tournaments?

On Wed, Mar 22, 2023, 7:31 AM Hahn, Paul manynote@wustl.edu wrote:

"In sports, what strategies could exist? I'd imagine something more
like... team B tells team X to play badly against team C, because the
tiebreaker won't make X win anyway. Thus if say, the Smith set is ABCX,
then it's possible that X losing more heavily against C could make B win
instead of A. That's more like compromising, but it's not quite the same
thing."

AFAIK the majority of deliberate losing (or not winning as handily as one
is capable) in sports are to take advantage of side bets.  I can imagine
that in a double elimination tournament one might deliberately go over to
the loser's bracket to avoid a team one is particularly bad against, in the
hope that they'll be eliminated before you have to face them.  But that
means you have to fight your way through the loser's bracket, which means
more matches; I don't know that it would be worth it most of the time.

The other scenario I am aware of is that in chess and some other sports,
one can lose or not win as big to avoid having your rating increased, so
that (again) you get to face lesser opposition.  This definitely happens.

I'm not sure how much of this carries over to an election situation,
though.

--pH

-----Original Message-----
From: Election-Methods election-methods-bounces@lists.electorama.com On
Behalf Of Kristofer Munsterhjelm
Sent: Wednesday, March 22, 2023 8:03 AM
To: Forest Simmons forest.simmons21@gmail.com; EM <
Election-methods@lists.electorama.com>; Kevin Venzke stepjak@yahoo.fr;
Andy Jennings elections@jenningsstory.com; Colin Champion <
colin.champion@routemaster.app>; Andy Dienes andydienes@gmail.com
Subject: Re: [EM] Simple Tournament Proposal

On 3/22/23 05:00, Forest Simmons wrote:

Here's my suggestion for choice of tournament champion:

Lacking an undefeated team, elect the pairwise victor of the defensive
and offensive champs.

I'll have to investigate further, but my impression from working with
burial-resistant methods is that it's impossible to make a method that's
burial resistant (in the DMTCBR sense) without using positional data.

However, another important property to note is that the modes of strategy
very much depend on how the data is gathered. In an election situation,
burial is fairly easy: just change A>X>B>C>D>E>F into
A>B>C>D>E>F>X. But in sports, the analog would be that A decides to tell
B to "strategically defeat X", e.g. to score more goals against X (or
similar) to push X further down the ranking. Presumably any team B would
be doing its best to defeat X already, so "burial" doesn't really seem to
be a strategy in sports.

Thus it's not a problem that we don't have positional data, because we
don't need to defend against that particular strategy.

In sports, what strategies could exist? I'd imagine something more like...
team B tells team X to play badly against team C, because the tiebreaker
won't make X win anyway. Thus if say, the Smith set is ABCX, then it's
possible that X losing more heavily against C could make B win instead of
A. That's more like compromising, but it's not quite the same thing.

-km

Election-Methods mailing list - see
https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Felectorama.com%2Fem&data=05%7C01%7Cmanynote%40wustl.edu%7Cee6ae3e76d5743655c5008db2ad5e2b3%7C4ccca3b571cd4e6d974b4d9beb96c6d6%7C0%7C0%7C638150870360304884%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=hv3F8bg%2BjtQKHlWpl4fI2S2GtlX%2FdMb1KFY%2BgGrTN0o%3D&reserved=0
for list info

Election-Methods mailing list - see https://electorama.com/em for list
info

Is clone dependence a problem ... teaming or crowding in tournaments? On Wed, Mar 22, 2023, 7:31 AM Hahn, Paul <manynote@wustl.edu> wrote: > "In sports, what strategies could exist? I'd imagine something more > like... team B tells team X to play badly against team C, because the > tiebreaker won't make X win anyway. Thus if say, the Smith set is ABCX, > then it's possible that X losing more heavily against C could make B win > instead of A. That's more like compromising, but it's not quite the same > thing." > > AFAIK the majority of deliberate losing (or not winning as handily as one > is capable) in sports are to take advantage of side bets. I can imagine > that in a double elimination tournament one might deliberately go over to > the loser's bracket to avoid a team one is particularly bad against, in the > hope that they'll be eliminated before you have to face them. But that > means you have to fight your way through the loser's bracket, which means > more matches; I don't know that it would be worth it most of the time. > > The other scenario I am aware of is that in chess and some other sports, > one can lose or not win as big to avoid having your rating increased, so > that (again) you get to face lesser opposition. This definitely happens. > > I'm not sure how much of this carries over to an election situation, > though. > > --pH > > -----Original Message----- > From: Election-Methods <election-methods-bounces@lists.electorama.com> On > Behalf Of Kristofer Munsterhjelm > Sent: Wednesday, March 22, 2023 8:03 AM > To: Forest Simmons <forest.simmons21@gmail.com>; EM < > Election-methods@lists.electorama.com>; Kevin Venzke <stepjak@yahoo.fr>; > Andy Jennings <elections@jenningsstory.com>; Colin Champion < > colin.champion@routemaster.app>; Andy Dienes <andydienes@gmail.com> > Subject: Re: [EM] Simple Tournament Proposal > > On 3/22/23 05:00, Forest Simmons wrote: > > Here's my suggestion for choice of tournament champion: > > > > Lacking an undefeated team, elect the pairwise victor of the defensive > > and offensive champs. > > I'll have to investigate further, but my impression from working with > burial-resistant methods is that it's impossible to make a method that's > burial resistant (in the DMTCBR sense) without using positional data. > > However, another important property to note is that the modes of strategy > very much depend on how the data is gathered. In an election situation, > burial is fairly easy: just change A>X>B>C>D>E>F into > A>B>C>D>E>F>X. But in sports, the analog would be that A decides to tell > B to "strategically defeat X", e.g. to score more goals against X (or > similar) to push X further down the ranking. Presumably any team B would > be doing its best to defeat X already, so "burial" doesn't really seem to > be a strategy in sports. > > Thus it's not a problem that we don't have positional data, because we > don't need to defend against that particular strategy. > > In sports, what strategies could exist? I'd imagine something more like... > team B tells team X to play badly against team C, because the tiebreaker > won't make X win anyway. Thus if say, the Smith set is ABCX, then it's > possible that X losing more heavily against C could make B win instead of > A. That's more like compromising, but it's not quite the same thing. > > -km > ---- > Election-Methods mailing list - see > https://nam10.safelinks.protection.outlook.com/?url=https%3A%2F%2Felectorama.com%2Fem&data=05%7C01%7Cmanynote%40wustl.edu%7Cee6ae3e76d5743655c5008db2ad5e2b3%7C4ccca3b571cd4e6d974b4d9beb96c6d6%7C0%7C0%7C638150870360304884%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=hv3F8bg%2BjtQKHlWpl4fI2S2GtlX%2FdMb1KFY%2BgGrTN0o%3D&reserved=0 > for list info > ---- > Election-Methods mailing list - see https://electorama.com/em for list > info >
KM
Kristofer Munsterhjelm
Wed, Mar 22, 2023 7:58 PM

On 22.03.2023 18:54, Forest Simmons wrote:

Is clone dependence a problem ... teaming or crowding in tournaments?

In one sense, every method might be clone dependent. Suppose that
playing against, say a positional chess player is draining and requires
a lot of concentration. Then if you face a particular positional player
ten times instead of one, it might do such a number on your endurance
that even though you beat them all, you lose other contests you might
have won, thus making you lose in the end.

However, if we suppose that A>B always leads to A>B1, A>B2, A>B3 etc.,
then it depends only on the tournament format and not on your endurance
as a player. Round-robin tournaments where wins count x points, ties 1,
and losses zero would reduce to Copeland and could have crowding
problems. Accelerated systems (e.g. Swiss) would probably also be
vulnerable to the rating strategy that Paul mentioned, although this
definitely isn't my area of expertise.

I guess that elimination tournaments could also be clone vulnerable - it
would depend on the seed order. An interesting question would be: what
property needs to hold for a seed and bye system for the resulting
elimination tournament to be cloneproof? Does any such rule exist?
Dealing with byes in particular seems very tricky.

Seed systems also have other requirements, like strong players not
meeting too early, which could further constrain the field of viable
systems. While searching, I found this paper, but I have only cursorily
looked at it:
http://www.oxfordcroquet.com/tech/knockout3/What_is_the_Correct_Way_to_Seed_a_Knockout_Tournam.pdf

-km

On 22.03.2023 18:54, Forest Simmons wrote: > Is clone dependence a problem ... teaming or crowding in tournaments? In one sense, every method might be clone dependent. Suppose that playing against, say a positional chess player is draining and requires a lot of concentration. Then if you face a particular positional player ten times instead of one, it might do such a number on your endurance that even though you beat them all, you lose other contests you might have won, thus making you lose in the end. However, if we suppose that A>B always leads to A>B1, A>B2, A>B3 etc., then it depends only on the tournament format and not on your endurance as a player. Round-robin tournaments where wins count x points, ties 1, and losses zero would reduce to Copeland and could have crowding problems. Accelerated systems (e.g. Swiss) would probably also be vulnerable to the rating strategy that Paul mentioned, although this definitely isn't my area of expertise. I guess that elimination tournaments could also be clone vulnerable - it would depend on the seed order. An interesting question would be: what property needs to hold for a seed and bye system for the resulting elimination tournament to be cloneproof? Does any such rule exist? Dealing with byes in particular seems very tricky. Seed systems also have other requirements, like strong players not meeting too early, which could further constrain the field of viable systems. While searching, I found this paper, but I have only cursorily looked at it: http://www.oxfordcroquet.com/tech/knockout3/What_is_the_Correct_Way_to_Seed_a_Knockout_Tournam.pdf -km