Figure 2 - Funnel plot of the sample size for each study plotted against the estimated prevented fraction, PF (%) for the 19 studies included in the meta-analysis
From the following article
Further statistics in dentistry Part 8: Systematic reviews and meta-analyses
A Petrie, J S Bulman & J F Osborn
British Dental Journal 194, 73 - 78 (2003) Published online: 25 January 2003
doi:10.1038/sj.bdj.4809877
