Many charity annual reports are box-ticking exercises and most are "not visually stimulating", according to a survey by the accounting firm Deloitte.
Gaining Public Confidence, based on an overview of 50 reports selected from those of the 1,000 largest charities, says they often lack any connection to the accompanying statement of financial activities and do not disclose the major risks they faced.
The publication says that more than two-thirds of reports are visually "very dull", with little use of pictures and graphs to illustrate their message.
This is an improvement, it says, on the findings of a similar survey carried out the previous year, when four-fifths of reports were called dull.
According to the survey, almost two-thirds of charities that produce dull annual reports also fail to produce an attractive annual review document to compensate.
Deloitte says a high-quality annual report enables potential donors to see which charities are achieving their aims and which are not.
"These annual reports are an improvement on the previous year," said Reza Motazedi, head of charities and not-for-profit at Deloitte. "But there’s still plenty of scope to do better.
"In particular, charities need to spend more time on risk management and reserves policy.
"With reserves, it’s not enough to say ‘we’ve got 30 per cent of our annual expenditure in reserves so we’re okay’; and with risk management it’s not enough to include three lines saying that trustees have looked at the risk register."