Promotional figures for exhibitions: the numbers that convince press and sponsors

Every exhibition ends the same way: the show closes, the crates are packed, and somewhere a press release is waiting for a number. Most venues reach for the biggest one available, the total attendance during the run, and most journalists and sponsors have learned to read past it. A building total credits the building and says nothing about whether the exhibition itself did anything.

The figures that convince answer the question a sceptical reader is asking: what did this show change? Those figures exist and come from measurement. A venue that can produce them credibly has a claim that survives the follow-up question, which is rarer than a big number.

The lift: what the exhibition changed

The single most persuasive promotional figure is the attendance lift: how many more visits the venue saw during the exhibition period than it would have seen without it. It is also easy to get wrong, because the lift is only as honest as its baseline.

Comparing the run against the month before it opened mostly measures the calendar: school holidays begin, tourist season turns, the weather changes. A fair baseline is like-for-like: the same weeks in previous years, or a multi-year average for that season, so the comparison isolates what the exhibition did from what the calendar did anyway.

Zone-based counting sharpens the claim further. When a temporary exhibition is measured as its own space, the venue can report two distinct things: the lift the show created for the building, and the visit count for the exhibition itself. “The museum was busier” and “people came for this show” are different claims, and the sponsor paid for the second.

Dwell: the number nobody expects in a press release

Attendance says people came. Dwell time says they stayed. Journalists almost never see that figure, which is what makes it quotable.

Museum researcher Beverly Serrell’s work compiling dwell times across more than a hundred exhibitions, published in Curator in 1997, found that most visitors are “casual” rather than “thorough”: exhibitions routinely overestimate how long people spend at any given element. Against that backdrop, a show that measurably held its visitors has a real story to tell.

A claim of that kind might read: visitors spent on average [measured figure] in the exhibition, [measured multiple] the typical dwell of the surrounding galleries. That sentence does promotional work only if both numbers were measured, in zones, over the whole run. What dwell time reveals in a museum setting, including why low dwell in a flagship gallery is more common than curators assume, is a separate subject. For a temporary show the promotional point is simpler: how long visitors stayed makes a better boast than how many passed through.

New audience: the reach a sponsor is buying

The sponsor’s question is “who came, that wouldn’t have otherwise?” Reach into a new audience is what the sponsorship was for, so a total visitor count rarely answers it.

Repeat-visit measurement, which runs with visitor opt-in and never identifies anyone, can indicate in aggregate how much of the audience over the run had not visited the venue before. A show that pulls the loyal audience in one more time is a programming success. A show where a large part of the audience was new to the building is a marketing success, and for the sponsor’s report that indication of reach is often worth more than the total, because it is the part of the audience the exhibition alone can take credit for.

The same measurement, read after the run, answers the follow-up that separates a good show from a durable one: did the new audience come back?

Credibility: a promotional figure is a public claim

Public claims get checked: by a journalist before quoting, by a sponsor’s due diligence before renewing, and by a rival’s press officer with time on their hands. A number that cannot explain how it was produced becomes a liability once it is in a headline.

Credible exhibition figures share a production method: counted continuously across the whole run rather than sampled on good days; covering every entrance and open hour; zoned to the exhibition itself, not inferred from the building total; calibrated against manual control counts; and measured anonymously. With the only footfall method in Europe approved by a data protection authority, a public institution is not buying its press number with its visitors’ privacy.

Funders apply the same standard. Our guide to visitor figures for funders makes the case that a figure is a claim and auditability is its defence. The press release and the funder report should be able to cite the same number, from the same series, and survive the same scrutiny.

A few things not to do, each of which has cost some venue a correction: do not extrapolate a record day across the run; do not report visits as “visitors” when re-entries were counted; do not switch definitions mid-story (opening week counted one way and the total another); and round honestly, so that “more than 40,000” is a figure you measured. A promotional figure that later needs correcting costs more than the coverage was ever worth.

One measurement, three audiences

None of this requires a separate measurement effort. The same zone-based, anonymous counting that runs the venue day to day produces the exhibition’s promotional figures as a by-product: the lift for the press release, the dwell for the sponsor’s deck, the indication of new audience for the partnership renewal, and the auditable series behind all three for anyone who asks. Museum visitor analytics makes an exhibition measurable as its own space. Once it is, every show that closes leaves the marketing department numbers that are interesting because they are true.