Structured Metrics Metamodel (SMM) is a publicly available specification from the Object Management Group ( OMG). Measures are comparable evaluations and, as such, are critical to software engineering and architecture driven modernization. Software measurement methods produce comparable evaluations of software or application artifacts. Counts such as number of screens, lines of code, number of methods, etc. all quantify the size of artifacts along a single dimension... The goal of SMM is to facilitate the interoperability of measurements of software artifacts.
See more on dedicated documents : SMM specifications, SMM request for proposal