A method including receiving designation of an input node for which a node value is generated from collected data, an option node to which a node value is arbitrarily provided, and an estimation target node to be a target of a node value estimation, in a graph including nodes and directional edges; and identifying a directional edge for which a conditional probability is to be acquired to measure the node value of the estimation target node, from among the directional edges, by traversing a directional edge that can propagate an effect to a node value from the estimation target node. The identifying includes, for the option node, traversing both a directional edge that can propagate an effect if a node value is provided to the option node and a directional edge that can propagate an effect if a node value is not provided to the option node.