The majority of charity annual reports are "very dull" to look at, according to a study from business advisory firm Deloitte.
Surveying the Sector is based on analyses of annual reports from 50 of the UK's 1,000 biggest charities by income. It says large amounts of text and few pictures often render reports impenetrable, and only 24 per cent of the charities surveyed use one or more graphs to bring the text to life.
"The vast majority of the trustees' annual reports were very dull to look at, consisting mainly of long sections of narrative not broken up by the use of pictures, charts, colour or highlighting," it says.
The report adds that, although charities are complying with most regulatory reporting requirements, they are missing a valuable opportunity to give donors a greater insight into their work.
Only 40 per cent of charities provide details of the major risks they face, it says.
Mary Reilly, head of third sector practice and a partner at Deloitte, said: "Charities need to do more to communicate to donors and other stakeholders, particularly in light of current economic conditions. The annual report is an ideal opportunity."
Brian Lamb, a sector communications consultant, said he was disappointed at the findings. "It's a bit much to expect supporters and beneficiaries to plough through a report full of long wedges of text," he said.
"You could have a short, pithy report that communicates what the organisation does and its impact in a vibrant and engaging way."
David Martin, marketing director at disability charity Papworth Trust, said: "I still see a lot of reports that are stuck in the 20th century, wasting lots of money and time producing something a lot of people are not going to read."