How Kelly builds the market consensus
Kelly's consensus is each book's price with the vig removed, averaged across the books quoting the same line, with sharper books weighted more.
Updated November 6, 2026
Removing the vig
A book's prices on both sides of a market add up to more than 100%. The extra is the book's margin, the vig. Kelly removes it from each book's prices with the power method, which never gives a negative probability, and keeps the other standard methods (multiplicative, additive, Shin and more) for when you ask for one by name.
The consensus
The no-vig probabilities of the books quoting the consensus line are averaged, with sharper books weighted more. Fewer than two books on a market means no consensus: the market reads "too few books" and shows no consensus numbers.
From the consensus Kelly derives the break-even probability at a price, the median hold across books, and how far the market has moved since its first price.
Where it shows
Per-book prices show only on askkelly.ai. The API, MCP and other sites get the derived values: the consensus, the hold, the break-even and the move.