Break Accuracy: Optimizing the Sorting Power of Preliminary Rounds Using Tapered Points

by R. Eric Barnes, Paul Kehle, Nick McKenny and Chuan-Zheng Lee • HWS

Ideally, preliminary rounds at tournaments sort teams so that the best teams break into elimination rounds. At the World Championships of debate, the scoring system during the nine preliminary rounds does a poor job of sorting teams accurately. Adding additional rounds would increase the accuracy and fairness, but this is impractical. Using mathematical models and computer simulations of tournaments, we show that using a slightly different scoring system over the nine preliminary rounds would improve the accuracy of the break even more than would doubling the number of preliminary rounds to 18. Other implications and insights into tabulation and sorting accuracy are also discussed.

Section 9: Conclusions

According to all intuitive metrics of accuracy that we investigated, the Early Taper scoring system significantly improves the accuracy and fairness of who breaks at a tournament like the WUDC.  Overall, the improvement is not just significant, it is truly dramatic.  Changing to an Early Taper scoring system would do more to improve the accuracy of the break than would doubling the number of preliminary rounds to 18.  And, it would do this at essentially no cost.  Although initially unfamiliar, debaters would very quickly adapt to understanding that they need a different number of points to break.  (Interestingly, straight 2nd place results will still break in ET.)

Additionally, an Early Taper system will produce pairings within the elimination rounds that have fewer imbalanced rooms; fewer rooms will have either unusually strong or unusually weak sets of teams.  This is because the ordering of teams within the break also gets much more accurate.  Really, one has to feel sorry for the teams in the status quo who break high and then get seeded against the top team on 17, like in 2012 when Monash B broke 48th as the top team on 17, and then won the tournament.[38]  So, the elimination rounds will be fairer using ET, making it more likely to have the best performing teams advance into later elimination rounds.

Moreover, by using the Early Taper system, the influence of speaker points is significantly reduced.  The size of the bubble will be reduced by more than half, limiting the impact from an element of debate scoring that appears tainted by bias and discrimination.

There will, undoubtedly, be some people who argue against changing the scoring system at Worlds.  A variety of reasons will likely be offered.  But, in reality, the strongest force in the way of the Early Taper system being adopted is simply inertia.  It is the same force that accounts for the United States still using the imperial system of measurement.  People are resistant to change, but one way of making it clear that irrational inertia is preventing the change is by a simple thought experiment.  Imagine that the Early Taper system was the well-established way that tournaments are being run, and then imagine that someone suggested that we switch away from ET to a system that is identical to what we are actually doing now, the same points awarded in every round.  How would this proposal fare?  It’s hard to even imagine someone arguing for it, saying: “Yes, I acknowledge that according to multiple independent and intuitively compelling metrics, giving the same points in every round will do a much worse job in creating an accurate break, but it’s still something we should switch to because of whatever-other-reason-you-want-to-give.”  The proposal wouldn’t stand a chance.

R. Eric Barnes – Hobart and William Smith Colleges

Paul Kehle – Hobart and William Smith Colleges

Hugh N. Mckenny – Hobart and William Smith Colleges

Chuan-Zheng Lee – Stanford University

[38]  Performance of others who were the top team on 17:  in 2020, Belgrade A made finals; in 2019, Princeton A made quarters (after they made finals in 2018); in 2018, Sydney A made quarters; in 2016, London Union B made semis; in 2015, Stanford A made quarters; etc.  In short, the top teams on 17 don’t belong seeded in the 40s.

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