The NPDA Audit Measures

For a full description of the NPDA audit measures please visit www.rcpch.ac.uk/NPDA

Understanding the Caterpillar Plots

If you choose to view the results for a particular NPDA audit measure via the "Caterpillar" chart type option you will notice that its appearance is quite different to the other views. In the Caterpillar Plots ICSs are ranked according to performance in the measure, with the most adherent shown on the right hand side of the graph. The performance in the measure (“compliance”) is shown by the vertical axis. Each ICS is represented by a dot, with a vertical bar above and below the dot representing uncertainty (statistically the “95% confidence interval”) in this measurement of performance.

Although ICSs are ranked for presentation, the purpose of the plot is to demonstrate the variation rather than to describe differences between ICSs with statistical confidence. Readers should be therefore use these plots to assert differences between ICSs only with the utmost of caution.