[cpher]

This is awesome! Kudos to you and the team (I assume you had help?). Yeah, I'm sure the tie breaking procedures drove you crazy. Imagine the rules committee meetings when they discussed all of them. :) How did you manage the complexity of the rules in your mind? I'm curious as to how you went from rules => mental model/entities => code. Did you use a formal process?

[mbostock]

Thanks, and yes, this was a collaboration with Kevin Quealy and Shan Carter.

The development process was incremental: first create a simple representation of the league (conferences, divisions, teams) and schedule (games, outcomes), then implement the necessary metrics (win percentage, strength-of-victory, etc.) and filters (e.g., head-to-head, common games), then finally the tie-breaking algorithm itself.

The incremental approach let me test the parts independently and reduce the amount of hair-pulling debugging unlikely scenarios. Though, there was still plenty of that… Fortunately the NFL has an official playoff computer I could use to test my implementation (for a single, complete scenario).