We need to track how many times or what percentage of times a certain issue caused a test case to fail. Please consider providing ability to use tags on test results (similar to Pivotal Tracker labels in stories). A solution would be to chart the trend of test case success (without tag filtering) vs failure activity provided existence of a test result tag on the failures.
It would be identical to the current Test Results chart - but to filter the test failures based on the tag, symptom, or cause. The practicality of this: Sometimes issues are not 100% within engineering's control, due to dependability and availability of interfaces with 3rd parties. Getting these trends help QA and product teams determine what to consider in improving reliability of product and service.