The figure has two square panels. Panel 1 is on the left and Panel 2 is in the center. Each panel has Dimension Y on the left hand side and Dimension X on the bottom of the square. A key on the right identifies the nature of five circles within each panel: Patient population, Efficacy sample, Effectiveness sample, Clinican A patients, and Clinician B patients.
Within Panel 1, the patient population is represented by a large circle. A much smaller circle in the upper left part of the large circle represents an efficacy study sample. An even smaller circle partially overlapping that smaller circle shows some of Clinician B's patients represented within the efficacy sample. (But some of B's patients are outside the efficacy sample). In the bottom right of the large circle, a smaller circle shows Clinician A's patients as part of the patient population; none of A's patients are within the efficacy study sample.
Within Panel 2, the patient population is also represented by a large circle. A fairly large circle in the upper left part of this large circle represents a large effectiveness study sample. A much smaller circle that falls entirely within it shows Clinician B's patients, all completely within the effectiveness sample circle. In the bottom right of the largest circle, a smaller circle partially overlaps the effectiveness sample and shows most of Clinician A's patients represented within the effectiveness sample, but a few falling outside it.