Methods, systems, and apparatus, including computer programs encoded on computer storage media, for a search engine for identifying analogies. One of the methods includes: receiving data that includes a set of user selected features and a user selected feature weight for at least one of the user selected features; generating a reference vector based on the received data; determining a level of similarity between the generated reference vector and each of a plurality of analogy vectors that each represent a potential analogy; providing, for output on a display of a user device, a set of one or more analogies based on the determined level of similarity; receiving a subsequent request to evaluate the set of one or more analogies based on a common attribute; determining, for each of the one or more analogies, a representation of the common attribute for each analogy over a time period; and providing, for display on the user device, a representation of the common attribute for each analogy over the time period.