1.4Risk-Based Test Strategy

The Principle

You cannot test everything. Risk-based testing allocates effort to the areas where bugs would cause the most damage.

Risk Calculation

Risk = Likelihood of Failure x Impact of Failure

Likelihood factors:
  - Complexity of the code
  - Frequency of changes
  - Developer experience with the area
  - Number of integration points
  - History of bugs in this area

Impact factors:
  - Number of users affected
  - Revenue impact
  - Regulatory / compliance implications
  - Reputation damage
  - Data loss potential

Applying Risk to Test Allocation

Risk Level	Test Approach	Example
Critical	Full automated coverage + exploratory + performance + security	Payment processing
High	Automated E2E for main paths + manual edge cases	User registration, search
Medium	Automated smoke tests + manual for new changes	Admin tools, reporting
Low	Automated visual regression + spot checks	Static content pages