Ranking SCT performance

I outlined the general procedure followed by NAQT
in issuing Division I ICT invitations in a previous
message. The key thing there (and the only thing, for
Division II) is that we rank all participating teams
according to their "SCT performance." The question is
always asked, "well how do you do that?" And we never
answer, precisely. But, here's the basic idea, hopefully
forestalling the annual barrage of "but we beat so-and-so head
to head; why are they invited and we aren't? or "we
finished in 4th place -- why was the 5th place team in our
region invited first, and why was the 7th place team in
another region invited?"

Ranking teams
statistically within tournaments isn't too hard, especially
tournaments that play full round robins and don't wind up
splitting their field later into different groupings for
secondary round robins; doing so across tournaments with
greatly differing strengths of field is a challenge. We
need to attempt it however, and wish to be as fair as
possible.

For the record, official order of finish within an
SCT is not itself a factor in how we rank SCT
"performance," for the purpose of ranking teams in invitation
order. That ranking is largely a factor of points scored
per tossup heard and bonus conversion, with an
adjustment for strength of schedule, so that teams from
different sectionals may be compared, and we try to
minimize statistical advantages to teams who fatten their
tossup numbers against opponents who collectively rate
as below the average team across all teams in their
division at sectionals, and minimize the statistical
disadvantage to teams whose numbers are presumably deflated by
facing better-than-average opponents. By whatever
percentage a team's actual opponents throughout the
tournament average out to be better or worse than the
overall average for all teams in the same division (and
playing on the same question set; Division II teams in
mixed-division fields excepted) across all tournaments, to the
same degree a team's initial rating of points scored
on tossups (not bonus conversion averages, which are
not affected by opponents' strength) is adjusted up
or down. We also then tweak a little bit based on
actual won-loss percentages, which usually has little
effect, but can move a team up or down in relative
rankings a little bit as a reward or punishment for
compiling a won-loss record much different from what
statistics would predict. (i.e., you'll get a little boost
in your ranking if you win most of your close
matches, and have your ranking a little deflated if you
lose most of your close ones. It rarely happens that
our rankings diverge wildly from a tournament's order
of finish, though it is fairly common that we will
rank teams adjacent in official standings in reverse
order for purposes of ICT invitations.

It was an
unfortunate necessity this year to be rather more subjective
in trying to compare Division II teams who played
only other Division II teams, on Division II
questions, with Division II teams who played in a mixed
field, on Division I questions. Basically, statistics
there are apples and oranges and can't be compared. So
we ranked both types of Division II teams
separately, and apportioned invitations between the two types
using our best judgment and considerations such as
field size, and the amount of statistical gap between
teams above and below in the rankings of the two types.
It is probably true nonetheless that sectionals that
were unable to provide separate play for their
Division II teams did make it somewhat harder for those
teams (other than the champions) to rank highly in the
invitation derby.

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