Total Time on Test Plots

Abstract

In the 1970s the total time on test (TTT) plot, and its theoretical counterpart, the scaled TTT transform, was presented by R. E. Barlow et al . as a tool for model identification based on data representing lives of nonrepairable equipment. It has been used when analyzing different aging properties, optimising replacement policies and studying test statistics. Generalisations of the TTT plot have also been used for analysis of data from repairable units. It has also been suggested as a tool for the selection of active factors in design of experiments. In this paper we give an overview of TTT plotting and its practical and theoretical applications. A wide range of references are suggested for further reading.

Long‐term surveillance of SUDEP in drug‐resistant epilepsy patients treated with VNS therapy

“…All analyses were performed after pooling definite, probable, and possible SUDEP, except sensitivity analyses focusing on definite and probable SUDEP only. The hypothesis that SUDEP rates decrease with time on VNS Therapy was first assessed by testing for a decreasing SUDEP hazard rate over follow-up time 12 and applying the Mann-Kendall nonparametric trend test to the SUDEP rates by year of follow-up. 13 In addition, the 95% CI was calculated for the rate ratio of the last 8 years postimplantation divided by the first 2 years postimplantation with the view to compare our findings to those of the 2 previous reports of SUDEP in patients undergoing VNS that used that methodology.…”