Software metrics are a critical tool for building reliable software and assessing measurable software quality, especially in complex domains. Software metrics are important for many reasons, including measuring software performance, planning work items, and evaluating productivity. Within the software development process, software metrics are related to the four functions of management: planning, organization, control, and improvement. The ultimate goal of software metrics is to afford continuous insight into products and processes. A useful metric typically provides a numerical assessment of the effectiveness of the underlying software or process.