June 19, 2026 | News | PHD
Congratulations, Angela Carollo!
Angela Carollo from the Laboratory of Fertility and Well-Being at the Max Planck Institute for Demographic Research (MPIDR), successfully defended her doctoral thesis, “Statistical Analysis of Time-to-Event Data with Multiple Time Scales“, at Leiden University. In her thesis she introduces a statistical model that addresses an important gap in the literature on statistical models for time-to-event data.
Jutta Gampe, Angela Carollo, Paul Eilers and Hein Putter after the successful defense. © private
Survival and event history models are used to analyze the occurrence of events over time, and time is a key component of these models. Time is often recorded over multiple time scales. For instance, in a clinical follow-up of cancer patients, the occurrence of death can be analyzed over time since cancer diagnosis, since treatment, or according to age. Processes involving multiple time scales are commonly found in medical and epidemiological studies, as well as in sociodemographic studies of the life course.
To overcome limitations of traditional models in such settings, in her thesis Angela proposed a statistical model that simultaneously incorporates multiple time scales. The model is complemented by statistical software that facilitates its use in applied research. She used the proposed model to analyze mortality of cancer patients, as well as transitions from non-marital cohabitation to marriage or separation. The empirical analyses demonstrate that noteable patterns in the data emerge from the simultaneous analysis of event occurrences across multiple time scales.
A significant part of Angela's dissertation was completed while she was working in the Laboratory of Statistical Demography headed by Jutta Gampe.
Angela Carollo’s thesis was supervised by Hein Putter (Leiden University) and Jutta Gampe (MPIDR).
Angela with the committee and her paranymphs Nicole Hiekel (second from the left) and Kelsey Wright (to the right of Angela). © private
Related Publications
Carollo, A.; Eilers, P. H. C.; Putter, H.; Gampe, J.:
Statistics in Medicine 44:1-2, 1–15. (2025)
Carollo, A.; Putter, H.; Eilers, P. H. C.; Gampe, J.:
Sociological Methods and Research, 1–31. (2025)
Carollo, A.; Putter, H.; Eilers, P. H. C.; Gampe, J.:
Statistical Methods in Medical Research 34:11, 2145–2162. (2025)
Carollo, A.; Eilers, P. H. C.; Gampe, J.:
Software. The Comprehensive R Archive Network: CRAN. (2024)
Upcoming Publication
Carollo, A.; Eilers, P. H. C.; Putter, H.; Gampe, J.: "TwoTimeScales: an R-package for smoothing hazards with two time scales" arXiv e-prints 2603.13009. (2026). DOI: 10.48550/arXiv.2603.13009