Yes, I'd be glad to.
I'm not certain what exactly you're thinking of in terms of accountability, but as we say, these tribunals are three-member panels generally. Generally the hearings are open to the public. Often a treaty will set it up such that one member is appointed by one country, the other is appointed by the investor, and the presiding member will either be by consent of the parties or, if they can't consent, by the ICSID appointing one for them.
The hearing is in public, and then there is this process of annulment. If people feel there is a need to have a review process or an appeal process, decisions are made public, and there is a very active community that looks at, examines, and critiques these decisions.
You will find increasingly that arbitrators cite past decisions. It is not a formal precedent system such as we have in domestic law, but it is becoming increasingly so. So there is a developing, coherent body of law so that we can know much better and predict whether, if we do this certain thing, it will be potentially considered expropriation or will potentially violate a treaty obligation.
I think that's probably all part of the accountability process. I don't know whether there are any particular aspects you're thinking of, but if there are I'd be glad to address them as well.