Clinical Trials

❘❙❚■ Chapter 30 | Missing DataFigure 2. Mean response over visit (full dataset: Dataset I).190 Group AGroup B180Mean response1701601501 2 3 4VisitDatasets with missing valuesWe derived a second dataset (Dataset II) from observations that were MCAR bygiving each participant a 20% chance of dropping out of the study before thesecond visit (irrespective of response and treatment group). Participants attendingfor the second visit were given a 20% chance of dropping out before the third visit,and participants attending for the third visit were given a 20% chance of droppingout before the final visit.Dataset III is an MAR scenario. All participants with an observed value >150 unitsat the first visit were continued to the second visit, whilst all participants with anobserved value