This statistical survey of a large sample of 1,660 bilateral investment treaties (BITs) identifies the main parameters of ISDS regulation in BITs; traces their emergence, frequency and dissemination over time; and highlights past and recent country-specific treaty practice. The survey finds among other things that many countries define the procedural framework thinly compared to advanced domestic procedural frameworks, despite a broad trend toward greater regulation in treaties of parameters of ISDS. Many treaties offer foreign investors a range of procedural choices, such as a choice between arbitration fora.

The survey also highlights the diversity that characterises the design of ISDS: over a thousand different combinations of rules regulating ISDS can be found in only 1,660 bilateral treaties –, with variation found both at editorial and substantial level. Differences in policy approaches between countries are the source of some of this variance, but it appears that much of it may not reflect differences in policy.

The study also found little evidence of general convergence of approaches towards regulating ISDS in BITs, or indeed much development in the BIT negotiating practice of a number of countries. A different approach, characterised by significantly more thorough ISDS regulation and pioneered by some countries, seems to spread increasingly in multilateral IIAs and more comprehensive treaties.