TD CORNER

By Tim Just

Humanized Pairings Redux

Let's check out those pairings from the April TD Corner. You can catch another glimpse of both the wallchart and the pairings on-line (http://www.uschess.org/tds/tdcorner05apr.php) or in the April supplement (pages x-xi).

Because this column hits cyberspace first (www.uschess.org/tds/tdcornerindex.php), the pundits on the USCF Tournament Direction forum (www.uschess.forums) did an early dissection of those pairings to correctly determine that Pairings B was the work of a human. Microchip wonder WinTD (v. 4.02) made pairings A. The players in pairings C got their board assignments from SwissSys (v. 6.081). Before we take a look at the Forum and e-mail (uscfrulebook@yahoo.com) comments, let's take a peek at the background surrounding these pairings.

BACKGROUND

The event was a 7-section class tournament with 30 minutes between rounds. Rounds 1-4 had been paired by WinTD for all the sections. This was the last round of the M/X section. In Round 4 Christopher won his game by forfeit over Albert, the victim of an auto mishap. To give Albert some dignity, Christopher was given a one-point bye for Round 4 and Albert was withdrawn from the tournament. For the money round the section now had 10 players ready to determine who gets to slice and dice the prize fund pie. The pairings program spit out Rajen-Stanislav on Board 1. So, the top 3.0 tournament leader (Stanislav at 2543), is dropping down 425 rating points past the 2.5 score group to the second-highest-rated player in the 2.0 score group (Rajen at 2018) to play for first-place prize money. All the colors work. The TD did announce that the pairings would be a bit odd for Round 5, given the small number of players and large number of rounds. I was the TD and those last-round $$$ pairings were way on the other side of peculiar from my point of view; therefore, despite the fact that I rarely, if ever, override a pairings program, in this case…

EDITED COMMENTS

From Bill Smythe: “It (pairings B) must have been done by a human, who was tired of solving problems … and simply threw up his hands ….”
Yep!?—T.J.
From Bill Smythe:  So the “raw” (natural) pairings in this case would be:

Of course, these pairings are unacceptable, but they make a good starting point when calculating the effect of transpositions.

“Compared to the raw pairings, which pairing, A or C, involves a smaller transposition for each player? Throw in the fact that all the colors are correct with pairing A, while two of them are bad with pairing C, and we seem to have a STRONG argument for pairing A over pairing C.”

From Harvey Lerman: Minimizing the difference in scores of paired players is much more important that alternating colors, especially in the last round of a 5-round event, when one expects 3-2 in colors. That’s why events of an odd number of rounds are so much better than those with an even number.”

From Tom Ewers: “I first did the pairings by hand, and came up with pairings as in C. After analyzing A and B, I then entered the entire crosstable into SwissSys and it also generated C.

“Note, while entering the round-by-round results and doing the pairings for the next rounds, SwissSys did not generate the same pairings as in the crosstable for Rounds 3 and 4. I know I looked at one such pairing and thought the crosstable had it correct and SwissSys was incorrect.”

Since neither program (WinTD or SwissSys) produced illegal pairings, the question becomes which set of pairings is better?—TJ.

I think the title to the discussion should be: How do you choose the odd chessplayer(s) and his opponents?

From Robert Sutter:
My Ideal Pairings:

	Stanislav	3.0	Aleksanda	2.5
	Angelo	3.0	Christopher	3.0
	Rajen	2.0	Igor	3.0
	Dushyan	2.0	William	2.0
	Lawrence	1.5	Walt	1.0
	Richard	1.5	Andrew	0.5

“One may legitimately ask why I rank (my) “IDEAL” PAIRINGS” better that PAIRING SET “A”… SET “A” gives more players their due color. Basically, the “IDEAL” pairings feature the smallest (scoregroup) point differential at the top of the wallchart and still balances the colors of every player (2W/3B, 2W/2B, or 2W/3B). Especially if we are pairing the fifth and final round of the tournament, it is most fair that the top player in the top point group (Stanislav) face the strongest possible opponent; that is, an opponent with 2.5 points (Aleksandra) is more desirable than an opponent with 2.0 points (Rajen).”

From Tim Just: Given these divergent opinions I have to ask: What is more important here? Colors? Scoregroups? Last round $ pairings? Transpositions? With 20-20 hindsight, I can see that the 5^th edition of the rules could have used some improved guidelines to indicate which rules takes priority when push comes to shove in making pairings.

Further comments can be posted on the USCF forums or e-mailed to uscfrulebook@yahoo.com.