Fig 2.

Calibration performance (as measured by the E/O statistic) of a diagnostic prediction model for deep vein thrombosis,⁴⁵ over all studies combined and in each of the 12 studies separately. E=total number expected to have deep vein thrombosis according to the prediction model; O=total number observed with deep vein thrombosis; I²=proportion (%) of variability in the ln(E/O) estimates in the meta-analysis that is due to between-study variation (genuine differences between studies in the true ln(E/O)), rather than within-study sampling error (chance)