Close  
Figure 3: Trial sequential analysis on effectiveness on transdermal fentanyl. Trial sequential analysis on effectiveness on transdermal fentanyl, of 29 randomized controlled trials (marked with black dots) illustrated that the cumulative Zcurve crossed the required information size after four trials, and the required information size was calculated to 174 (the vertical line). (NOTE: The red line is the trial sequential analysis monitor boundary according to a relative risk reduction of 20%, type I error of 5% and type II error of 20%. The red horizontal line is the Zscore of ± 1.96, equal to twosided P = 0.05. Xaxis: The number of patients randomized, Yaxis: The Zscore) 
