FUNNELPERFORM: Stata module to produce funnel plot for institutional comparison

funnelperform computes data and plots a funnel plot as defined by Spiegelhalter 2005. A scatter plot of an indicator values value is plotted against a measure of their precision pop, typically the sample size, together with a target line and control limits (contours), that narrow as the sample size gets bigger. The plot graphically tests whether each value of the indicator is extracted from a target distribution specified by the options.