Participants
How many? Who are they? Reason for attending?
Who is in the room shapes what is possible, and you need to know that before you design the session.
Participants is the practical question of who will actually be in the room: how many people, who they are, what their relationship is to each other and to the topic, why they are attending, and whether they chose to come or were told to. These are not just logistics; they are design inputs. A session for eight people who volunteered and are curious looks completely different from a session for thirty people with mixed seniority levels who were told to attend.
The number matters more than people expect. Activities that work beautifully for twelve become unwieldy for twenty-five. A fishbowl works for twenty but not for six. Breakout groups change in character depending on whether you have three groups of four or eight groups of three. Do the arithmetic on your exercises with the actual headcount, not an assumption.
The reason for attending shapes the energy in the room from the start. A participant who chose to be there brings different energy than one who was sent. A participant who has been asking for this kind of session for months brings something different than one who is in the middle of a crisis. Knowing this in advance lets you open the day in a way that meets people where they are.