Fig. 1From: Risk-adjusted CUSUM control charts for shared frailty survival models with application to hip replacement outcomes: a study using the NJR datasetCUSUM charts calculated for quarterly revision rates in the three NJR datasets: DePuy ASR Resurfacing Cup (black), Biomet M2A 38 (blue) and in-control dataset (magenta), over the period 2005-12. The control bounds (solid red lines) are estimated by the parametric bootstrapBack to article page