Cities measure event economic impact to justify stadiums. Organizers should measure it for a more practical reason: the travel spend your event creates is your negotiating position — with hotels, with sponsors, with the city — and most organizers walk into those rooms with a guess. The estimate takes an afternoon.
The method
- Travel mix: pull ticket or registration postcodes. Everyone beyond a reasonable same-day radius is a travelling party.
- Party size and occupancy: attendees per order approximates party size; divide travelling headcount by people per room for your vertical — families run high, conferences run near one.
- Nights: your event's span plus shoulder nights. Multi-day events reliably produce arrivals the night before.
- Rate: what rooms near your venue actually cost on your dates — check your own weekend, not the annual average.
- Multiply: travelling rooms × nights × rate is the lodging line. Add parking, meals, and transport at conservative per-party figures if you want the full number.
A calibration point
In one mid-size event market we measured directly, a single peak weekend generated roughly 550 room-nights — one event, one town. Run your own numbers before assuming your event is too small to matter; organizers are consistently low on this estimate, because the spend is invisible to them by construction.
What the number is for
Hotels negotiate differently with an organizer who can document the demand they bring. Sponsors price differently against a total-economy figure. And the organizer prices differently: once you know your event moves six figures of lodging spend, the question of why none of it earns for you stops being rhetorical. The guest pays the same rate either way; the question is whether you earn on it — and at around 6–8% of every booking made through your page, measurement is how you find out what you should have been earning.
From estimate to negotiating position
The number changes conversations the day you can defend it. With hotels: 'our event generated roughly N room-nights last year' — documented from postcodes and market observation — reframes the block negotiation from favor-seeking to demand-delivery, and desks respond with terms accordingly. With the city or tourism board: events that quantify their lodging impact qualify for marketing co-op funds and bid support that unquantified events never hear about. With sponsors: adjacent-spend totals expand what your audience is worth on paper, and thus what attention on it costs. And internally: the number ranks your own priorities — a six-figure lodging economy makes the confirmation-page panel obvious; a five-figure one still usually clears the effort bar, because the effort is an afternoon.
- Present ranges, not points — 'between X and Y room-nights' survives scrutiny; false precision invites it.
- Refresh annually: the growth rate of the number is itself an asset in every pitch.
- Cite the method in one line wherever you use the number; auditable beats impressive.