Evidence-Guided Reform: Surveying the Empirical Research on Arbitrator Bias and Diversity in Investor-State Arbitration

As a diffuse, sprawling, relatively opaque and increasingly polarized legal order, the international investment regime, with its thousands of largely bilateral investment treaties, ad hoc system of adjudication – called investor–state arbitration or investor–state dispute settlement (ISDS) – and a decades-long legitimacy crisis and backlash against its practice make it a challenging phenomenon to accurately describe and assess. It also makes the identification and prioritization of its most problematic and reform-worthy areas of concern difficult to pin down. Without empirical data, the international investment regime has been, and to some degree continues to be, very susceptible to heuristics based on limited information, anecdote, and surface-level policy prescription.