The current best-known method for performing each operation — documented, visible, and always subject to improvement through kaizen. taiichi-ohno drew a sharp distinction between standardization (rigid, imposed from above, never changed) and standard work (documented by the workers themselves, improved by the workers themselves, changed whenever a better method is found). Standard work has three elements: takt time, work sequence, and standard work-in-process. It serves as the baseline from which improvement is possible — you cannot improve what you have not defined. This is directly connected to w-edwards-deming's concept of a stable process: a process must be in statistical control before it can be improved. Standard work also makes abnormalities visible: when everyone follows the standard, deviations are immediately apparent, triggering five-whys investigation.