5.

Trial sequential analysis on mortality in the 13 trials that administered low dose of vitamin D₃ (i.e. a dose less than 800 IU per day) 
 The diversity‐adjusted required information size (RIS) was calculated based on mortality in the control group of 10%; relative risk reduction of 5% in the experimental group; type I error of 5%; and type II error of 20% (80% power). No diversity was noted. The required information size was 110,505 participants. The cumulative Z‐curve (blue line) did not cross the trial sequential monitoring boundaries for benefit (red line) at any time. Accordingly, the crossing of the conventional statistical 5% boundary (the horizontal brown line) may be due to random errors.