Analysis of two well documented innovations-the transistor in consumer electronics and the jet engine in subsonic aircraft-leads to criteria which discriminate between profitable and unprofitable new technologies. Technological criteria include constraints removed and added by the innovation, and its capacity to stand alone. Business criteria include changes in existing operations and requirements for new ones, and whether the innovation provides market expansion or lower price. Applied to potential new technologies, these criteria indicate plausibility for a computerized car and implausibility for a US supersonic transport.