Establishing standards for evidence is critical for any academic or scholarly community. In DBIR, evidence must both meet high standards for internal validity, and yet also exhibit strong external validity in terms of being useful to or actionable by practitioners.
At different points in the research and development cycle, different types of evidence may be more or less appropriate. As with other aspects of DBIR, appropriate evidence standards need to be negotiated among partners, including perhaps funders and/or relevant policymakers.