Originally from Investment Treaty Arbitration and International Law - Volume 2

In international arbitration, arbitrators’ independence and impartiality—both essential elements to the arbitral system—have been described as opposite sides to the same coin.2 The test for independence tends to be an objective one, based on factual analysis in respect of arbitrators’ pre-existing financial or other relationship with one of the parties to the arbitration.3 Impartiality, on the other hand, requires a subjective consideration of whether there is any actual or apparent bias on the part of the arbitrator as a result of her mental predisposition towards the parties, subject-matter, or issues involved in the proceeding.4 Both independence and impartiality are directly tied to the concepts of conflict and bias in international arbitration.

Both international bar associations and established arbitral tribunals (and rules relating to ad hoc arbitrations) have made attempts to address bias in the context of arbitrators’ relationships with parties and/or counsel, while the issue of impartiality remains either inadequately addressed or addressed with conflicting views. For instance, the Rules of Arbitration of the International Chamber of Commerce (“ICC Rules”), those of the United Nations Commission on International Trade Law (“UNCITRAL Rules”), and of the International Centre for Settlement of Investment Disputes ("ICSID Rules"), all address the indeendence and impartiality of arbitrators, in addition to arbitraor challenges.5 Subject-matter bias or issue conflicts6 in the context of independence and impartiality, however, has been the subject of ongoing debate, adn is generally not addressed by arbitral rules. This is partially why parties are challenging arbitrators on "issue conflicts" with more and more frequency.