Last Saturday, DePaul played the Missouri SCT site, a combined D1/D2 field using the D2 set. Of DePaul's opponents, only WUSTL A and C averaged 20 PPB on the D2 set, with over half coming in under 15 PPB.

And what did this leave DePaul with? The second-highest strength of schedule (SOS), not in the Missouri field, but of every team that played SCT. This is due to a confluence of three serious flaws with the SOS calculation, which I'll lay out below.

To review, SOS is calculated as tossup points per tossup heard (TUPPTH) of the teams you played in their other games, divided by the tossup points per tossup heard over all SCT sites.

1. Tossup points per tossup heard is a heavily field-dependent measure of team strength. The current SOS calculation cannot differentiate reasonably strong teams in good fields from weak teams in weak fields. Looking at the current D-values list, Chicago D (15.69 PPB) has a worse TUPPTH than Ohio State C, Vanderbilt A, and Colorado A (10.61, 10.00, and 8.41 PPB, respectively). So playing Chicago D, a respectable opponent by any standard, lowers the SOS of Chicago D's opponents more than if they had hypothetically been able to play OSU C or Vandy A. That double-penalizes teams at the Northwestern SCT -- not only do they have to face a fairly strong team as their weakest opponent, but their SOS takes a huge hit for it.

2. The effect of point 1 is exacerbated in round-robin scheduling. Let's take the example of two four-team round robin tournaments. The first has four strong teams in the 17-19 PPB range. The second has two of those teams, and then two teams in the 10-12 PPB range. In the first tournament, each team will get roughly half the tossups per round, so each team's opponent's TUPPTH will be ~5.00 (assuming as many powers as negs). In the second tournament, the two strong teams will get about 80% of the tossups against the two weak teams and 50% against each other. The weak teams will get 20% against strong teams and 50% against each other. So a strong team will have played one strong team (~7.72 TUPPTH in other games) and two weak teams (~3.64 TUPPTH in other games), for a SOS of ~5.00. So a strong team gets the benefit of beating up weak teams without any hit to SOS! This effect would be further exacerbated by a final between the two strong teams, which will boost their SOS without dramatically reducing their TUPPTH.

More generally, in a round robin, the number of tossup points scored by your opponents in other games is equal to {(10 x Tossup Conversion Rate) + (5 x Power Rate) - (5 x Neg Rate)}. This measure doesn't really vary too much from site to site, since even in games between relatively weak teams, almost all tossups are still converted, and power rates aren't significantly lower than games between good teams.

3. There is no D2 conversion for opponents' TUPPTH in the SOS calculation. Following from the last sentence of point 2, the tossup conversion rate in combined fields is artificially raised, since a D1 team's opponents are being measured on their ability to convert D2 tossups rather than D1 tossups. It seems fairly clear that if you had forced the Missouri site to play on D1 questions, many more tossups would have gone dead, and the SOS of all teams would be much lower. However, teams at all non-combined sites are being judged on their ability to convert D1 questions, so comparing those two measures seems illogical.

How should NAQT fix the strength of schedule calculation for future years? Use points per tossup heard rather than tossup points per tossup heard, which will incorporate a non-competitive measure of team strength (bonus conversion) and adjust for the strength good teams in very competitive fields. Additionally, NAQT should apply a D2 conversion factor to the SOS of combined fields to avoid comparing field strengths on two very different sets.