Fig. 1
From: Dynamic updating of clinical survival prediction models in a changing environment
Sample follow-up times for 18 simulated individuals under cohort with replacement (left) and new cohorts (right) frameworks. On the left, most individuals are part of the Q1, Q2 and Q3 cohorts. When an individual has an event (e.g. individual 9 at time 5.7 months), they are replaced by a new person at the start of the following month (e.g. individual 10). On the right, each quarterly dataset consists of different individuals and those joining the new cohort after the first month of the quarter have a shorter follow-up time. For example, individuals 5 and 6 join at the beginning of month 3 and are followed up for one month or until an event occurs