In recent years, many computer system failures have been caused by software faults that were introduced during the software development process. This is an inevitable problem, since a software system installed in the computer system is an intellectual product consisting of documents and source programs developed by human activities. Then, Total Quality Management (TQM) is considered to be one of the key technologies to produce more high quality software products. Generally, a software failure caused by software faults latent in the system, cannot occur except for certain special occasion when a set of special data is put into the system under a special condition, i.e. the program path including software faults is executed. The quality characteristic of software consistency is, that computer systems can continue to operate regularly without the occurrence of failures on software systems. In this paper, we discuss a quantitative technique for software quality/consistency measurement and assessment, as one of the key software consistency technologies, which is a so-called software consistency model and its applications.