Deterioration: a statistical quality control analysis

The structural basis of deterioration demonstrated with control line emphasizes the need and importance of a scientific approach of judgement to achieve ultimate control over a (not necessarily) physical system/process. Evaluation of corrective action models through two statistical measures of deterioration, namely vertical and horizontal, reveals that a system can be controlled by taking appropriate correctives only at the early stage of vertical measure, contrary to à la mode at horizontal measure. A sequence of vertical–horizontal–vertical measure formed due to a shift of control-line towards out-of-control region makes the statistical basis of deterioration.