synthesising evidence from multiple evaluations

When the best is the enemy of the good: The Nature of Research Evidence Used in Systematic Reviews and Guidelines

This paper, written by Marcel P. J .M. Dijkers for the Task Force on Systematic Review and Guidelines, examines the approach in evidence-based practice of using only the "best available" evidence and argues that this strongly disadvantages rehabilitation programs because of their nature. He goes on to state that the focus on the use of only the 'strongest' research designs shifts the focus away from researchers asking 'What is the best design to answer this research question?'