9.1 Why secondary evidence matters

Organizational data describe activity within one system. They may show which services were used, which products were purchased, or which customers were retained, but they do not automatically explain the surrounding population, economy, industry, policy environment, or comparable practice.

Secondary evidence can provide:

• population denominators and projections;
• industry or sector benchmarks;
• economic and demographic context;
• geographic boundaries;
• established definitions and measurement standards;
• evidence about similar interventions; and
• information about populations not represented in internal data.

More sources do not automatically strengthen an analysis. Each source should answer a defined information need and be sufficiently comparable for the intended use.