In his book, *Testing Business Ideas,* [[David J. Bland]] introduces assumption mapping as a sway to identify "leap of faith" assumptions. These are the riskiest assumptions that need to be tested first ([[Test the riskiest assumptions first]]). An assumption map is a four box. From left to right the x-axis ranges from "strong evidence" to "weak evidence," and top to bottom the y-axis ranges from "more important" to "less important." Items listed in the upper-right are the "leap of faith" assumptions. When mapping assumptions, it's important that all assumptions are mapped relative to one another. [[Teresa Torres]] mentions this exercise in *[[Torres - Continuous Discovery Habits|Continuous Discovery Habits]]*.