ABSTRACT: This document replaces SR-TSY-001547, Issue 1, January 1990, but contains NO TECHNICAL CHANGES from that document. It has been reissued strictly to conform to the Telcordia Technologies document format.

The analysis of any process or product depends on the judicious use of measurements, i.e., data. Organizations can spend tremendous resources on collecting data without careful consideration of why they are engaged in these activities and how the data are to be analyzed once collected. This can result in organizations proposing elaborate guidelines and requirements for the collection of data while giving only vague indications of the purpose of the data collection.

This Special Report (SR) takes the general point of view that the main reason for collecting reliability and quality data is to analyze it in such a way that objective conclusions and decisions can be made. The SR presents the Telcordia view of methods for measuring, analyzing, and modeling software reliability and quality. An attempt has been made to avoid overly complex models; however, in some cases, successful use of the methods does require software that is not included. This document applies to network switching elements (local switch, tandem switch, signal transfer point, etc.), transport products, operational support systems, or other software-controlled systems used by a typical Local Exchange Carrier (LEC).