Estimating counterfactuals for evaluation of ecological and conservation impact: an introduction to matching methods

• Published in: Biological reviews of the Cambridge Philosophical Society Vol. 96; no. 4; pp. 1186 - 1204
• Main Authors: Ribas, Luiz G. S., Pressey, Robert L., Bini, Luis M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.08.2021
• Subjects: Biology; Conservation; Conservation biology; Control equipment; counterfactual; Ecology; Environmental science; Estimation; impact evaluation; Matching; matching method; Nonparametric statistics; non‐parametric method; Quasi-experimental methods; quasi‐experimental; matching method; counterfactual; impact evaluation; non-parametric method; quasi-experimental
• ISSN: 1464-7931; 1469-185X; 1469-185X
• DOI: 10.1111/brv.12697

ABSTRACT Matching methods encompass non‐parametric approaches to estimating counterfactual states through a rigorous selection of control units with similar characteristics to units submitted to an intervention. These methods enable comparisons between treated and control units in a way that facilitates understanding of causal relationships between interventions and outcomes. Matching methods have been used only recently in ecology and conservation biology, where such applications changed the way the field investigates causal questions, for example, in impact‐evaluation studies. However, the strengths and limitations of matching methods are not well understood by most ecologists and environmental scientists. Herein, we review state‐of‐the‐art matching methods aiming to help fill this gap in understanding. First, we present relevant theoretical concepts related to matching methods and related subjects such as counterfactual states and causation. Next, we propose guidelines and strategies for the application of matching methods in ecology and conservation biology. Finally, we discuss the possibilities for future applications of matching methods in the environmental sciences.