Visitor figures are under the microscope once again after a summer of dramatic headlines about miscounting and museum chiefs being in crisis talks over falling attendances.

Several of London's national museums have suffered a drop in visitor numbers, while Arts Council England highlighted in its annual report a major fall in exhibition attendances at venues run by its National Portfolio Organisations.

The news that London's National Portrait Gallery had significantly miscounted its visitor numbers, after it failed to record 600,000 attendees in the last financial year alone, added to the sense of crisis.

But while there has been a slight downward trend in museum attendance from a peak in 2014-15, this is not borne out by all museums, according to the Department for Digital, Culture, Media & Sport (DCMS)'s annual Taking Part survey.

"The picture is not black and white," says Megwen Roberts, the data director at cultural strategy and research agency Morris Hargreaves McIntyre, which analyses museum visitor trends. "It is complex data to communicate, as there is a lot of detail that sits behind it. Trends may be down sector-wide, but that is not true of everyone."

Taking Part, a face-to-face survey of households in England, is regarded by many data experts as a good indicator of the sector's performance. Anne Torreggiani, the chief executive of the Audience Agency, a not-for-profit organisation specialising in data and insight, says the survey underpins a lot of the agency's work.

"Taking Part has a big sample, it is year on year, asks the same questions and is weighted across the country," she says. "It's a sample, but it is a good indicator of what is going on across the nation."

This year's Taking Part revealed engagement with museums in London was lower than when the report began in 2005, with all other regions in England showing an increase except the West and East Midlands and the east of England. The north-west enjoyed the greatest increase, rising from 40.4% in 2005-06 to 56.5% last year.

London suffering

Sharon Heal, the director of the Museums Association, notes changes were made to the questions about museums in this year's Taking Part survey, meaning some data is not comparable. That said, visitor numbers in London have been falling, she says.

"To understand trends in visitor figures, we need reliable and comparable data and statistics," says Heal. "We need to ask the same questions of the same institutions and people, so that we can compare year on year and map any trends.
 
"The picture is different across the UK - figures appear to have dipped in London but elsewhere there have been record-breaking attendances. We need to see the whole picture."

Figures from VisitEngland published in August show a 1% decline in visitors to museums and galleries for the second consecutive year. This was largely the result of a fall in visits to museums and galleries in London, which suffered a 4% drop last year.

According to the tourism body, visitors to all London attractions, including museums and galleries, fell for the third consecutive year (2% in 2017, 1% in 2016 and 3% in 2015). It says that last year, the decline was partly driven by the four terror-related attacks in London between March and September.

Yorkshire/Humber (7%) reported the highest level of visitor growth last year. This rise was buoyed by visitor attractions in Hull, which was the UK City of Culture in 2017 and is home to the redeveloped Ferens Art Gallery. Attractions in southern England also fared well, with the south-west reporting a 5% rise in visitor numbers and the south-east a 4% increase.