The objective of this standard is to provide the software community with defined measures currently used as indicators of reliability. The predictive nature of these measures is dependent on correct application of a valid model. This standard presents a selection of applicable measures, the proper conditions for using each measure, the methods of computation, and the framework for a common language among users. It moreover provides the means for continual assessment of the process, as well as the products, at each phase of the life cycle. By emphasizing early reliability assessment, this standard supports methods through measurement to improve the product reliability. Successful application of the measures is dependent upon their use as intended in the specified environments. Applicability is not restricted by the size, type, complexity, or criticality of the software. Typical life cycle phases based upon ANSI/IEEE Std 729-1983 , are used to illustrate when each of the measures may be applied. Errors, faults, and failures serve as primitive units for the majority of the measures.