Fig. 2
From: When to keep it simple – adaptive designs are not always useful
Timeline of the first example trial (ISRCTN 11889464) if participants were recruited at a rate of two per month (a) and one per month (b). Stage 1 enrolment represents the pre-planned number of individuals who would provide information at the interim analysis. The red part of the x axis denotes stage 2 participants who are recruited prior to the interim analysis being started; the green part denotes stage 2 participants who are recruited after the interim analysis starts (and who thus may benefit from the adaptive design)