JDS Journal of Data Science 1683-86021680-743X1680-743X School of Statistics, Renmin University of China JDS1137 10.6339/24-JDS1137 Statistical Data Science An S-Curve Method for Abrupt and Gradual Changepoint Analysis JiangLanlanjiang@ucdavis.edu1∗ KennedyCollincjkennedy@ucdavis.edu1 MatloffNormannsmatloff@ucdavis.edu1 University of California, Davis, USA Corresponding author. Email: lanjiang@ucdavis.edu or cjkennedy@ucdavis.edu or nsmatloff@ucdavis.edu. 2025972024231225242 Supplementary Material

The ZIP file contains all code needed to reproduce the figures and results of the experiments.

18420241942024 2025 The Author(s). Published by the School of Statistics and the Center for Applied Statistics, Renmin University of China.2025 Open access article under the CC BY license.

Changepoint analysis has had a striking variety of applications, and a rich methodology has been developed. Our contribution here is a new approach that uses nonlinear regression analysis as an intermediate computational device. The tool is quite versatile, covering a number of different changepoint scenarios. It is largely free of parametric model assumptions, and has the major advantage of providing standard errors for formal statistical inference. Both abrupt and gradual changes are covered.

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