Risk Based Testing is where testing activities focus on the most important tests that will mitigate the highest amount of risk. Its goal is to increase test effectiveness while potentially resulting in fewer tests, thus reducing cost.
A Risk Based process will provide an approach for:
Evaluating and improving the quality of requirements;
Improve both test effectiveness and efficiency;
Monitoring and reporting progress in reducing risk;
Adjusting risk reduction actions (e.g. test scope) based upon the effectiveness of prior actions or additional knowledge.
Gain consensus on high risk requirements
The key here is "scoring" your requirements with a risk like we do with other general project risks. We then can manage a risk profile on these requirements and how we are going to mitigate them... with testing.
Time spent to analyze and assess requirements
Time spent to identify risks associated with requirements
Time spent to identify and execute risk mitigation approach