If evidence-based research is to be more than an academic exercise, and is to make a useful contribution to the discipline and practice of software engineering, then it needs to lead to evidence that can be used to:

• Deliver useful guidance about good practice, so that developers can determine what benefits they might get from using particular techniques, and be aware of the key factors influencing any effects;

• Enable organisations to make evidence-informed decisions about the adoption of policies related to software development and procurement;

• Underpin the work of standards bodies. Because a systematic review is a secondary study, with its value coming from the objective synthesis of the outcomes of primary studies, these needs can only be met successfully if they are supported by:

• An objective and rigorous process for producing evidence; and • A set of sound empirical studies that address the given topic.