Abstract: Methods, systems, and apparatus, including computer programs encoded on computer storage media, for updating a node structure. One of the methods includes: maintaining, in memory and for each indicator of a first entity, a corresponding tree structure identifying the corresponding indicator and attributes affecting the indicator, the tree structure having i) parent nodes representing indicators that are not actionable for the first entity and ii) leaf nodes representing an action for the first entity to adjust the indicator; determining whether a first tree structure includes a link with a second tree structure; determining a weight for a link between the first and second tree structures; and creating the link between the first and second tree structures that includes the weight; and maintaining the first and second tree structures and the link for generating a recommendation of an action to adjust a value of the first indicator for an entity.