To monitor the respect of coding standards, add the Rules Compliance widget to your dashboard:
The RCI is a second-level metric calculated by Sonar. It gives a ratio between weighted violations and the number of lines of code.
Clicking on one of the severities or on the the total number of violations opens the Violations Drilldown.
To Rules Compliance Index (RCI) gives you an overview regarding the respect of coding standards. To understand how the RCI is computed, see Rules Compliance Index definition.
Use the differential views to monitor added violations.
You can set your coding standards through the (active checks, severity, etc.) through the Quality Profiles administration page.