National Portrait Gallery: counting error underestimates visitor numbers

Amount of attendees appeared to halve during 2017-18 when actual figure only fell by 10%

An apparent steep decline in visitors to the National Portrait Gallery was the result of an error by an automated third-party footfall counting system which underestimated the true yearly figure by hundreds of thousands.

According to data collected by Ipsos Retail, the number of visitors to the gallery in central London almost halved during 2017-18, when in fact it had only fallen by 10%.

The company had thought the number of visitors was 2.1 million in 2015-16, 1.9 million in 2016-17 and 1.1 million in 2017-18. It was also believed that visitor numbers from April to June this year had fallen by 28% on the same period last year.

The perceived fall in visitors led to concerns from the government, the gallery’s main source of funding, and the gallery’s reputation was also affected at a time of dwindling visitor numbers to the biggest national museums.

Now, however, it appears that poorly monitored faulty equipment was to blame. The revised figures show the gallery actually had 1,691,547 visitors in 2017-18.

An automatic counting system at the main entrance of the building uses optical sensors, an infrared beam and other methods to gauge how many people come to the gallery each day. The gallery raised its concerns about the system’s accuracy when it observed discrepancies between the number of visitors it recorded and those counted manually as having visited the BP Portrait Award 2018 exhibition in July.

“Further manual counts undertaken by the gallery indicated that the system was significantly undercounting visitors through the main entrance,” a spokesperson for the gallery said.

An internal investigation by Ipsos showed that a fault with a sensor over the main door had occurred in March 2017 and was recorded the following month. The system was repaired, but went on to fail an accuracy audit in July 2017 that revealed inconsistencies between the systematic and manually observed counts. An Ipsos employee, however, entered the results of the audit as a pass rather than a fail so no further action was taken.

“The counting system over the main entrance has now been replaced and corrective actions are being taken by Ipsos Retail Performance to safeguard against a repetition of events,” a gallery spokesperson said.

A statement from Ipsos said: “Ipsos Retail Performance has worked with the National Portrait Gallery for over 17 years and is collaborating closely to make adjustments to the under-reported number of visitors and to agree preventative actions to safeguard against any repetition of events. Ipsos Retail Performance continues to monitor footfall figures at The National Portrait Gallery.”


Mattha Busby

The GuardianTramp

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