1. A computer-implemented method for proposing a value to a user, the method comprising: mapping, by one or more processors, each of multiple bids for an item type with a percentage of bidding processes for items of the item type that were won using that bid; generating, by the one or more processors, a graph of the mapping; identifying a rectangle that has a first corner at a specific bid value and a second corner opposite to the first corner at a point on the mapping, and that is larger than any other rectangle that has a corner at the specific bid value and an opposite corner on the mapping; identifying, by the one or more processors, a first bid associated with the point on the mapping or with a corresponding point in a normalized mapping; and outputting, the one or more processors, a proposed value for the bidding process to a user, the proposed value generated using the first bid.