Figure 2From: Variations and inter-relationship in outcome from emergency admissions in England: a retrospective analysis of Hospital Episode Statistics from 2005–2010 Example of a funnel plot visually exploring the issue of variability in all-cause 1-year mortality rate for acute myocardial infarction (AMI) between providers. 27.7% of hospitals lay outside the 95% (green lines) confidence intervals (green) and 11.4% of hospitals lay outside the 99.8% (red lines) confidence intervals. Further statistical analysis determined whether the probability that the number of hospitals outside the confidence intervals was significant (both p < 0.0001).Back to article page