4-59. Effective assessment for stability operations incorporates both quantitative (observation-based) and qualitative (opinion-based) indicators. Human judgment is integral to assessment, especially in operations where the civil population plays such a prominent role. A key aspect of any assessment is the degree to which it relies upon human judgment and the degree to which it relies upon direct observation and mathematical rigor. Rigor offsets the inevitable bias, while human judgment focuses rigor and processes on intangibles that are often key to success. The appropriate balance depends on the situation—particularly the nature of the operation, its included stability operations, and available resources for assessment.