Abstract It is over 20 years since seminal papers argued that conservation effectiveness could be revolutionised by using the best available evidence. Ironically, in this time there has been little work critically evaluating the evidence for evidence‐based conservation (EBC) itself. Does it really improve conservation outcomes and provide a return on investment? In this perspective, we explore three interpretations of this question. First, we consider evidence for the overall EBC paradigm. Case studies and research, largely from disciplines other than conservation, support the intuitive conclusion that evidence‐based practice can improve outcomes. But issues such as deficiencies in the underlying evidence and biases in those assessing it mean this will not always hold true, even where all principles of evidence‐based practice are followed. Next, we consider the question of how much to invest in EBC. Generating and using evidence takes time and money; this investment will not be worthwhile in all situations. Understanding the cost‐effectiveness of EBC in different contexts is an important direction for future work. Finally, to address the question of how to carry out EBC to maximise its benefits, we present a theory of change that describes the key stages in the EBC process. Each step is a potential barrier to EBC, but also provides insights into enabling actions. The theory of change identifies key assumptions that can be tested with a range of research methods, both to inform the application of EBC and generate mechanistic evidence on its effectiveness. Practical implication : Over the next 20 years, we encourage further investment in generating evidence on EBC, especially on contextual questions such as when it is effective and worth the investment and how it should be carried out. We must also strengthen the underpinning evidence base so it can inform decisions where appropriate.
Taylor et al. (Wed,) studied this question.