Gather credible evidence
Ensuring that collected data is credible depends on a number of factors such as how the questions were posed, sources of information, conditions of data collection, reliability of measurement, validity of interpretations, and monitoring and quality control procedures. Triangulation is the key concept for a multiple-method approach for gathering credible data. It is thus of particular importance to do all the efforts in describing adequately the attributes of information sources used, the rationale for their selection; establishing clear procedures for data collection; avoid over-generalising results, etc.