Abstract Presents a reply to Ishikawa' s commentary which proposed that the reliability model could be improved by the use of feedforward concepts and that maintainability may be applied to the study of internal control systems. Explanation of control concepts; How reliability model encompasses the feedforward concept; Dispute against Ishikawa's contention that the engineering concept of maintainability is adaptable to application in the study of internal control systems.
Barry E. Cushing (Wed,) studied this question.