First, an institutional arbitration is governed by arbitration rules which provide clarity and certainty on a range of procedural issues. For this reason, complex procedural issues, such as challenges to arbitrators, consolidation of arbitration proceedings, joinder of parties, etc, can typically be decided more reliably in an institutional arbitration. On the other hand, in an ad-hoc arbitration, the adjudication of complex procedural issues is often riddled by doubt and uncertainty.
Source: Barandbench
