What is the framework for product metrics? What are the measurement principles?

A fundamental framework and a set of basic principles for the measurement of product metrics for software should be established. Talking in terms of software engineering:

- Measure provides a quantitative indication of extent, amount, dimension, size of an attribute of a product or process. Measure is established when a single data point has been collected.
- Measurement is an act of determining a measure. Measurement occurs when one or more data points are collected.
- Metric is the quantitative measure of the degree to which a system, component or process possess a given attribute. It relates individual measures in some way.
- Indicator is a metric or combination of metrics providing insight into software process, project or product itself.

There is a need to measure and control software complexity. It should be possible to develop measures of different attributes. These measures and metric can be used as independent indicators of the quality of analysis and design models.

Product metrics assist in evaluation of analysis and design models, gives an indication of the complexity and facilitate design of more effective testing. Steps for an effective measurement process are:
- Formulation which means the derivation of software measures and metrics.
- Collection is the way ti accumulate data required to derive the metrics.
- Analysis is the computation of metrics.
- Interpretation is the evaluation of metrics.
- Feedback is the recommendation derived after interpretation.

Metrics characterization and validation includes:
- Metric should have desirable mathematical properties.
- The value of metric should increase or decrease in the manner in which a software characteristic increases when positive trait occurs or decreases when undesirable traits are encountered.
- Metric should be validated empirically.