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In 2010, Diogo R. Ferreira participated on a chess ratings competition offered by [https://en.wikipedia.org/wiki/Kaggle Kaggle] <ref>[http://www.kaggle.com/c/chess Chess ratings - Elo versus the Rest of the World - Kaggle]</ref> and made it to 4th place <ref>[http://blog.kaggle.com/2010/11/30/how-i-did-it-diogo-ferreira-on-4th-place-in-elo-chess-ratings-competition/ How I did it: Diogo Ferreira on 4th place in Elo chess ratings competition | no free hunch]</ref> . His approach is based on the [https://en.wikipedia.org/wiki/Pairwise_comparison Bradley-Terry model], but with a slightly different interpretation of what the [[Playing Strength|strength]] of a player is, and with a custom procedure for estimating that strength <ref>[[Diogo R. Ferreira]] ('''2010'''). ''[http://web.ist.utl.pt/diogo.ferreira/chess/ Predicting the Outcome of Chess Games based on Historical Data]''. [https://en.wikipedia.org/wiki/Instituto_Superior_T%C3%A9cnico IST] - [https://en.wikipedia.org/wiki/Technical_University_of_Lisbon Technical University of Lisbon]</ref> . In his [[ICGA Journal]] paper, ''Determining the Strength of Chess Players based on actual Play'' <ref>[[Diogo R. Ferreira]] ('''2012'''). ''Determining the Strength of Chess Players based on actual Play''. [[ICGA Journal#35_1|ICGA Journal, Vol. 35, No. 1]]</ref> , Ferreira elaborates on strength estimation based on a per move basis with the help of a strong chess program and distribution of gain. A gain was defined by the [[Score|score]] difference of [[Houdini|Houdini's 1.5]] fixed depth 20 ply search of all consecutive positions along the game-record, alternating assigned to the player who made the move. Four algorithms for different purposes were defined: