The Project: 512 Paths to the White House by Mike Bostock, The New York Times
This is a behind-the-scenes look at the creation of a visualization by The New York Times:
“The space of electoral college calculators is fairly well-trodden, so at first it seemed hard to do something new. The big problem here is the combinatorial explosion (2^n): even if you consider only nine states, you have 512 possible outcomes! So, you don’t offer much insight by simply enumerating outcomes or allowing undirected exploration. The challenge is to preserve minute details (micro) while providing an effective visual summary (macro).
We settled on a binary tree early on, but it wasn’t until Shan had the idea of collapsing parts of the tree into “decision” nodes that the design clicked. By pruning subtrees below the 270-vote threshold, you reduce the complexity substantially. More importantly, you get a much faster sense of what matters: who wins! And from there it was “just” a matter of implementation and refinement.