What are the most useful software development metrics? [closed]

Question

I would like to track metrics that can be used to improve my team’s software development process, improve time estimates, and detect special case variations that need to be addressed during the project execution.

Please limit each answer to a single metric, describe how to use it, and vote up the good answers.

Answer 1

       

_{(source: osnews.com)}

Answer 2

ROI.

The total amount of revenue brought in by the software minus the total amount of costs to produce the software. Breakdown the costs by percentage of total cost and isolate your poorest performing and most expensive area in terms of return-on-investment. Improve, automate, or eliminate that problem area if possible. Conversely, find your highest return-on-investment area and find ways to amplify its effects even further. If 80% of your ROI comes from 20% of your cost or effort, expand that particular area and minimize the rest by comparison.

Costs will include payroll, licenses, legal fees, hardware, office equipment, marketing, production, distribution, and support. This can be done on a macro level for a company as whole or a micro level for a team or individual. It can also be applied to time, tasks, and methods in addition to revenue.

This doesn't mean ignore all the details, but find a way to quantify everything and then concentrate on the areas that yield the best (objective) results.