This POSTnote examines the need for an evidence-based approach to conservation management. Evidence-based practice requires the collection and analysis of valid, impartial data regarding past decisions, and the application of this knowledge to future decision making. Currently, there are no policies regarding the use of an evidence base for conservation interventions. It is recognised that decisions based on solid evidence and information have a higher impact and tend to be more cost-effective. A 2003 Department for Environment, Food and Rural Affairs report estimated the cost of controlling the invasive plant Japanese knotweed at £1.56billion, yet a 2006 systemic review found that the most widely used management techniques were largely ineffective in the long term. The majority of current, new conservation interventions are based on local or departmental knowledge, and on personal experience, but there has recently been a move to provide a large-scale evidence-based framework for conservation decisions. Evidence-based assessments are dependent on systematic reviews of the outcomes of earlier decisions about related issues. Systematic reviews based on a specific question attempt to identify high-quality research relevant to that question, and assess the evidence to provide a direction for future decisions.