Are these emergency department performance data real?

We have recently demonstrated that the distribution of total time spent by patients in emergency departments (EDs) in England shows a peak immediately prior to the current Department of Health target of 4 hours. We aimed to investigate whether this suggested that performance data were being manipulated. We collected data from 117 EDs, and 616 067 patient episodes were included in the analysis. Evidence of manipulation of performance data appears to be present in a small proportion of episodes, but because of the numbers involved, it could equate to over 50 000 episodes per year in EDs in England.