How to schedule parallel sessions at a conference

Start with clusters, not slots

Group accepted abstracts by topic first and only then assign times. A session with a coherent theme is easier to chair and easier for attendees to choose. Split a large topic into two sessions rather than mixing unrelated talks to fill a slot.

Find the clashes that matter

Some clashes are harmless; others empty a room. Check these before you publish.

• The same person presenting or chairing in two rooms at once.
• A keynote speaker’s parallel talk overlapping with another session from the same group.
• Two sessions on closely related topics running at the same time.
• Presenters who can only attend one day.
• Sessions from a single research group scheduled against each other.

Size rooms from expected interest

Ask which sessions are likely to be popular. Put them in the largest rooms rather than in the order they were accepted. If registration shows interest by topic, use it; if not, ask chairs and track leads.

Leave room to change

Withdrawals, illness and travel problems will move things. Keep one spare slot per day where possible and decide in advance who can approve a swap. Every change should update the record from which the website is generated, not a separate copy.

Worked example: grouping 60 abstracts into sessions

Suppose 60 abstracts have been accepted for oral presentation, and you have two rooms and four parallel slots of 90 minutes. Each session holds five talks of 12 plus 3 minutes, which fills 75 minutes and leaves 15 for changeovers. Four slots in two rooms give eight sessions and 40 talks. That is not enough for 60, so you need three rooms, or six slots, or shorter talks. Doing the sum first tells you what the timetable must look like before you start arguing about who speaks when. Then cluster the 60 abstracts by topic into twelve groups of five, and adjust where a group is too small or too large.

A simple method for finding clashes

Clashes are easiest to find by listing every person with a role in the programme and the slots in which they appear. A spreadsheet is enough for a small meeting, and a system that reads the programme is better for a large one. The method is the same either way.

• List every presenter, chair, organiser and discussant with a row per appearance.
• Sort by person and look for two rows in the same time slot.
• For each topic cluster, list the sessions scheduled against it and ask whether an interested attendee could go to both.
• Mark people who can only attend on certain days, and check that they are not scheduled elsewhere.
• Repeat the check after every change, since a fix in one place often creates a clash in another.

Session length, talks and changeovers

The arithmetic of a session is simple and often ignored. A 90-minute session with five 12-minute talks, 3 minutes of questions each and no buffer has only 15 minutes of slack, and a single late arrival uses it up. Decide whether the session has four or five talks based on the real buffer you want, and let chairs know that the schedule is a promise to attendees who are moving between rooms. If one talk overruns, the next presenter starts late, and people in the other room are waiting for a talk that has not started. Tell chairs to keep to time even when a discussion is lively.

Sizing rooms from expected interest

Use a small table to match each session to a room. Ask track leads to rate expected interest as high, medium or low, and use registration data if it shows topic interest. Give high-interest sessions the largest rooms, and put related low-interest sessions in the same slot in the smaller rooms.

Slot 1 (11:00) Session 1A Forecasting methods interest: high Room A (200 seats) Session 1B Groundwater interest: medium Room B (100 seats) Session 1C Data and models interest: low Room C (60 seats) Slot 2 (14:00) Session 2A Urban water systems interest: high Room A (200 seats) Session 2B Legacy datasets interest: low Room C (60 seats)

Session hopping and how to manage it

Attendees will move between parallel sessions to hear a specific talk. Decide whether you will accept it and support it, or discourage it. Supporting it means that chairs keep talks to the published times, the programme shows the exact time of each talk and the rooms are close to each other. If a session has no fixed order, hopping becomes impossible. Tell presenters that their time is fixed, and that moving a talk by ten minutes can affect people in another room. Some meetings ask attendees to move only between talks and not in the middle of one; a short sentence in the programme is enough.

Do not schedule against posters and keynotes

Poster sessions and keynotes are the parts of a programme that attract everyone, and are the most likely to be undermined by a clash. Keep parallel sessions out of the poster session, or make sure that poster presenters are not also speaking at the same time. Keep the keynote alone in its slot. Where a keynote is followed by a coffee break, place parallel sessions after the break, not immediately after the keynote, so that people have time to find their room.

A protocol for last-minute changes

Changes arrive during the meeting, and a written protocol keeps them under control. Name one person who can approve a change and one who updates the programme. Update the record first, then the website and signs, and tell affected presenters and chairs personally. If the change moves a session to another room, place a person at the old room to redirect people, and add a line to the online programme.

Change request What: [Session 2B moves from Room B to Room C] Why: [Room B has a technical fault] Approved by: [Programme chair] at [time] Updated: [website] [app] [signs] Informed: [chair] [presenters] [volunteers]

Check the programme as an attendee

Before publication, pick three attendee profiles, say a PhD student in one topic, a keynote speaker and a chair, and walk through their day. If any of them has a clash or a five-minute walk between rooms, adjust it.