Metrics are necessary to provide measurements of such qualities. Metrics can also be used to gauge the size and complexity of software and hence are employed in project management and cost estimation.

Process quality: Activities related to the production of software, tasks or milestones.

1. Process metrics are collected across all projects and over long periods of time.
2. They are used for making strategic decisions.
3. The intent is to provide a set of process indicators that lead to long-term software process improvement.

4. The only way to know how/where to improve any process is to:

   • Measure specific attributes of the process.

   • Develop a set of meaningful metrics based on these attributes.

   • Use the metrics to provide indicators that will lead to a strategy for improvement.

Product quality: Explicit result of the software development activity, deliverables, products.

1. Product metrics help software engineers to better understand the attributes of models and assess the quality of the software.
2. They help software engineers to gain insight into the design and construction of the software.
3. Focus on specific attributes of software engineering work products resulting from analysis, design, coding, and testing.
4. Provide a systematic way to assess quality based on a set of clearly defined rules.
5. Provide an “on-the-spot” rather than “after-the-fact” insight into the software development.

Objective Metrics:

1. They are non-negotiable – that is the way they are defined doesn’t change with respect to the niche or the type of endeavor they are being applied to.
2. Actual cost or AC is always the total cost actually incurred in accomplishing a certain activity or a sequence of activities.

Subjective Metrics:

1. These metrics are a relatively new precept and are more flexible than the rigid framework of the objective metrics. Subjective metrics do deal with performance but the approach is more tailored. For some enterprises the niche in which they function forces project management to change in order to adapt to the demands of the workplace