user12429: I have been following the controversy surrounding the pairings of Hou Yifan at the IOM chess tournament 2017. She was paired with 4 consecutive female players, this is following her last open swiss tournament outing in Gibraltar where she was paired with 7 female players from 10 pairings, including round 1 - 4 consecutive female-female pairing as in IOM 2017. 
The question is can we not design a simple non-deterministic swiss pairing system that does not penalise the "outliers" of the female population of players? It is clear that rules make it more likely for Hou Yifan to be paired with women as there is an elo gap in mean the population of male elite GMs and female elite GMs and the lowest elo on the highest score and highest elo on lowest score pairing pattern used increases the likelihood of these gender-specific pairings. Any ideas?
Surely we can create opt out for gender pairings which occur consecutively?

user12629: 
Surely we can create opt out for gender pairings which occur
  consecutively?

Yes, we could.  We can make whatever rules we like, after all.  But I don't think we should.
Such a rule would have to come at the expense of some other pairing rule.  We currently have rules that players cannot play each other twice, that players with equal scores should play each other, that colors should be equalized, etc.  Which of the existing rules are less important than equalizing which gender a player will play?
Such a rule would also imply that playing females is somehow undesirable, or gives an inherent advantage or disadvantage compared to playing males with the same rating.  I don't think these are views FIDE wants to encourage.
And any rule that makes things "non-deterministic" makes it harder for FIDE to verify that the pairings were not manipulated.  (If we did have such a rule, why would it not be deterministic?)

It is clear that rules make it more likely for Hou Yifan to be paired with women as there is an elo gap in mean the population of male elite GMs and female elite GMs and the lowest elo on the highest score and highest elo on lowest score pairing pattern used increases the likelihood of these gender-specific pairings.

First of all, people with "highest" and "lowest" scores are very unlikely to play each other.  Perhaps you meant "higher" and "lower".
Second, there are pairing rules about minimizing the number of people who get the same upfloat/downfloat as the previous round, or two rounds ago, so while this may be a factor for some players, it won't happen every round, or even every other round.
Third, in both Gibraltar and Isle of Man, she did not float (in either direction) in any of the rounds, so this was pretty much irrelevant.  It was sheer luck that she was paired with women.

user924: The current algorithms are deterministic. I have no idea why you would want a non-deterministic algorithm. The advantage of the deterministic ones we currently use is that they can be easily done by hand (and were done by hand until quite recently), so if a TD changes them manually that can be detected.
Gender of the players is not an input to the algorithm at all. It does not play a role whatsoever.
Hou Yifan had a very unusual draw in this year's Gibraltar and the first four rounds of Isle of Man; but that's just a coincidence. Something like that has never been noticed with any other women or other tournaments or other years.

12429: <p>I have been following the controversy surrounding the pairings of Hou Yifan at the IOM chess tournament 2017. She was paired with 4 consecutive female players, this is following her last open swiss tournament outing in Gibraltar where she was paired with 7 female players from 10 pairings, including round 1 - 4 consecutive female-female pairing as in IOM 2017. </p>

<p>The question is can we not design a simple non-deterministic swiss pairing system that does not penalise the "outliers" of the female population of players? It is clear that rules make it more likely for Hou Yifan to be paired with women as there is an elo gap in mean the population of male elite GMs and female elite GMs and the lowest elo on the highest score and highest elo on lowest score pairing pattern used increases the likelihood of these gender-specific pairings. Any ideas?</p>

<p>Surely we can create opt out for gender pairings which occur consecutively?</p>
 12629: <blockquote>
  <p>Surely we can create opt out for gender pairings which occur
  consecutively?</p>
</blockquote>

<p>Yes, we could.  We can make whatever rules we like, after all.  But I don't think we should.</p>

<p>Such a rule would have to come at the expense of some other pairing rule.  We currently have rules that players cannot play each other twice, that players with equal scores should play each other, that colors should be equalized, etc.  Which of the existing rules are less important than equalizing which gender a player will play?</p>

<p>Such a rule would also imply that playing females is somehow undesirable, or gives an inherent advantage or disadvantage compared to playing males with the same rating.  I don't think these are views FIDE wants to encourage.</p>

<p>And any rule that makes things "non-deterministic" makes it harder for FIDE to verify that the pairings were not manipulated.  (If we did have such a rule, why would it not be deterministic?)</p>

<blockquote>
  <p>It is clear that rules make it more likely for Hou Yifan to be paired with women as there is an elo gap in mean the population of male elite GMs and female elite GMs and the lowest elo on the highest score and highest elo on lowest score pairing pattern used increases the likelihood of these gender-specific pairings.</p>
</blockquote>

<p>First of all, people with "highest" and "lowest" scores are very unlikely to play each other.  Perhaps you meant "higher" and "lower".</p>

<p>Second, there are pairing rules about minimizing the number of people who get the same upfloat/downfloat as the previous round, or two rounds ago, so while this may be a factor for some players, it won't happen every round, or even every other round.</p>

<p>Third, in both Gibraltar and Isle of Man, she did not float (in either direction) in any of the rounds, so this was pretty much irrelevant.  It was sheer luck that she was paired with women.</p>
 924: <p>The current algorithms are deterministic. I have no idea why you would want a <em>non</em>-deterministic algorithm. The advantage of the deterministic ones we currently use is that they can be easily done by hand (and were done by hand until quite recently), so if a TD changes them manually that can be detected.</p>

<p>Gender of the players is not an input to the algorithm at all. It does not play a role whatsoever.</p>

<p>Hou Yifan had a very unusual draw in this year's Gibraltar and the first four rounds of Isle of Man; but that's just a coincidence. Something like that has never been noticed with any other women or other tournaments or other years.</p>
