Pair programming is a style of programming in which two programmers work side-by-side at one computer, continuously collaborating on the same design, algorithm, code, or test. One of the pair, called the driver, types at the computer or writes down a design. The other partner, called the navigator, has many jobs. One is to observe the work of the driver ± looking for defects in the work of the driver. The navigator has a much more objective point of view and is the strategic, long-range thinker. Additionally, the driver and the navigator can brainstorm on-demand at any time. An effective pair programming relationship is very active. The driver and the navigator communicate, if only through utterances, at least every 45±60 seconds. Periodically, it is also very important to switch roles between the driver and the navigator.