"you cannot control what cannot measure"  - Tom DeMarco

Software metrics deals with the measurement of software product and the process by which it is developed.

Effective management of any process requires quantification, measurement, and modeling. Software metrics provide a quantitative basis for the development and validation of models of the software development process. Metrics can be used to improve software productivity and quality.

"Software Crisis" [Arthur85]
Software development scenario is often characterized by

* schedule and cost estimates that are grossly inaccurate.
 * poor software quality, and
 * a productivity rate is slower than the demand for software.

Need for software metrics

Addressing "software crisis" requires

* accurate schedule and cost estimates
* better quality products
* higher productivity

All these can be achieved through more effective software management, which, in turn, can be facilitated by the improved use of software metrics. Information gained from the metrics can be used in management and control of the development process, which helps to improve results.

Software metrics can be classified as either product metrics(internal metrics) or process metrics(external metrics). Product metrics are measure of the software product measured from artifacts of the software, while Process Metrics are measures of software development process, such as overall development time, methodology and staff experience etc.

Swat4j automatically measures product metrics from Java source code. Automating measurement helps in a.) time saving b.) Consistent measurement c.) Lets us focus on the implications of  metrics rather than process of measuring. McCabe Cyclomatic Complexity, Halstead Effort/Volume, Object Oriented Metrics are some of the widely used metrics which Swat4j support. See Reference->Metrics for a complete list of metrics supported by Swat4j.

Swat4j advocates the use of software best practices and software metrics as predicates of software quality with a unique goal oriented model based quality model.Read about Quality Model .

Reference & further reading on Software Metrics
[Software Metrics] http://www.sei.cmu.edu/publications/documents/cms/cm.012.html
[History of Software Measurement] http://irb.cs.tu-berlin.de/~zuse/metrics/3-hist.html
[Software Measurement Guidebook] http://sel.gsfc.nasa.gov/website/documents/online-doc.htm