Its report, Feeding back? Learning from complaints handling in health and social care, published last week, reveals that numbers of complaints fell to 133,400 in 2006/7.
The report says an NAO survey found that of 88 per cent of adults in England who had contact with the NHS in the past three years, 87 per cent were satisfied, 13 per cent dissatisfied.
Of those dissatisfied, 35 per cent were unhappy with their GP, 17 per cent with a hospital doctor, and 11 with a dentist.
Just 5 per cent of dissatisfied patients made a formal complaint.
Comment below and tell us what you think
