The ACA has a few mandates on leader to participant ratios. These have been in place for many years in their various skills classes. They enforce these rules to ensure all their events have adequate safety. The rules are pretty simple:

• 1 Leader for every 10 participants With a qualified assistant
• 1 Leader can lead up to 5 participants without an assistant

To keep things simple - a 5:1 ratio of participants to leaders/helpers. There are some conditions where you certainly want a lower ratio. If you are leading beginners in whitewater, it really helps to have a few extra helping hands. Another good example would be leading a Team River Runner trip (disabled veterans), extra hands would provide a much safer and better experience as well. Always use good judgment in selecting your helpers and recruiting enough to make the trip safe and enjoyable. Here is the ACA reference to this golden rule: ACA Student / Instructor Ratio