Aims for customer satisfaction through early and continuous delivery of useful software components developed by an iterative process using the bare minimum requirements; examples of these methodologies include rapid application development (a type of rapid prototyping emphasizing extensive user involvement); extreme programming (xp—with phases of planning, designing, coding and testing); rational unified process (owned by ibm and has four gates—inception, elaboration, construction, and transition); and scrum (produces software in sprints with each day beginning with a meeting to monitor and control development efforts)