Over 500 films are released in US theaters each year, and many more are made and released on other platforms (broadcast, streaming, etc.). While many of those movies fail commercially (A.K.A. “flop”), many meet or exceed expectations. A film is the sum of many parts, from the subject matter, release timing, director, script, actors/performers and below-the-line crew. What determines the success of a film? The decision to make (“greenlight”) a film is a complicated process involving artistic considerations, production ambition and budget, actor availability, and studio relationships. Historically, studio executives have relied on artistic/commercial instincts and other heuristics like analyzing the performance of comparable films. By predicting return on investment (ROI)—the ratio of worldwide box office to production budget—we aim to offer quantitative guidance to movie studios and film-makers.