This plugin is deprecated since SonarQube 4.0 because the technical debt computation was implemented in SonarQube Core.
The plugin evaluates how much technical debt a project has. It consists of 4 advanced measures:
Clicking on an indicator brings the usual drill down.
The debt is first calculated on the basic axis: Duplication, Violations, Complexity, Coverage, Documentation and Design.
It is then summed up to provide a global measure.
Full details of axes calculation are available here.
The debt ratio gives a percentage of the current technical debt of the project versus the total possible debt for the project.
It allows you to better compare projects. For instance having $ 10,000 debt on a "small" project does not mean the same as the same debt on a big project.
This gives a monetary estimate of what it would cost to clean all defects on every axis (no more issues, no more duplications...).
This is the cost to pay down the debt, expressed in man days.
This gives a view of the debt distribution across the 6 quality axes through a pie chart.
Run a new quality analysis and the technical debt metrics will be fed.
A significant improvement would be to gather manual measures: see SONARPLUGINS-91.
Having a real cost to resolve for each rule would add a lot accuracy.