Births are difficult to predict even with rich survey and full-population register data
Elizaveta Sivak, Emily M. Cantrell, Thomas Emery, Javier Garcia-Bernardo, Flavio Hafner, Kasia Karpinska, Malte Lüken, Adrienne Mendrik, Joris Mulder, Hanzhang Ren, Varun Satish, Mark Verhagen, Angelica M. Maineri, Paulina Pankowska, Jasmin Abdel Ghany, Bruno Arpino, Giovanni Cassani, Julia Hellstrand, Katya Ivanova, Sanni Kuikka, Ana Macanovic, Charles Rahal, Felix C. Tropf, Roland J. Veen, Nicole Walasek, Daniël van Wijk, Kelsey Q. Wright, Emilio Zagheni, Henry Abbink, Emanuele Aliverti, Matteo Amestoy, Tilbe Atav, Nicola Barban, Sunnee Billingsley, Goan J. Booij, Louis Boucherie, Yael Broos, Li Ya Chang, Jamie C. Chiu, Chiara Ludovica Comolli, Boris Cule, Qixiang Fang, Dennis M. Feehan, Rachel Ganly, Erwin Gielens, Rolando M. Gonzales Martinez, Andrea Gradassi, Rosember Guerra-Urzola, Mario Guerra-Urzola, Stéphane Guerrier, Enamul Hassan, Vincent A. Haverhoek, Andrew T. Hendrickson, Amber Howard, Yuxuan Jin, Sayash Kapoor, Erik-Jan van Kesteren, Iris ten Klooster, Marie Labussiere, Lydia T. Liu, Tiffany Liu, Adam Maghout, Simone Meneghello, Lasse Mohr, Clara H. Mulder, Saul J. Newman, Jessica Nisén, Janis Norden, Mikkel Odgaard, Riccardo Omenti, Ozancan Ozdemir, Christina Pao, Paige Park, Gaia Penta, Juan C. Perdomo, Tanzir Pial, Alessio Piraccini, Federica Querin, Ziwei Rao, Christian Rellama, Adrien Remund, Frederieke Richert, Arnout van de Rijt, Mojtaba Rostami Kandroodi, Stijn J. Rotman, Lucas Sage, Germans Savcisens, Katrin Schwanitz, Steven Skiena, Alessandro Spata, Yannick Stadtfeld, Benedikt Stroebl, Gaetano Tedesco, Mathilde Theelen, Gianluca Tori, Abigail Tun-Mendicuti, Rishabh Tyagi, Keyon Vafa, Luiz Felipe Vecchietti, Linda Vecgaile, Willem R. J. Vermeulen, Maria-Pia Victoria Feser, Lionel A. Voirol, Thom B. Volker, Xinran Wang, Jiani Yan, Xinyi Zhao, Flora Zhou, Zuzana Zilincikova, Malvina Nissim, Matthew J. Salganik, Gert Stulp
Major life events have proven difficult to predict. Does this reflect limits of theory, data, and algorithms, or the large role of chance? We examine one outcome - having a child within three years - through a near-ideal setting for prediction: a data challenge where 147 researchers predicted births for Dutch residents aged 18-45, using survey data and full-population registers. Methods ranged from logistic regression to a large language model and transformers. Predictions were moderately accurate (best F1: register 0.59, survey 0.76); advanced models did not outperform classical ones; and the larger registers did not beat the survey. Simulating the stochastic biology of conception and pregnancy, we estimated a predictive ceiling (survey F1 ~ 0.86-0.94, register 0.88-0.96). Observed performance falls short of this ceiling, implicating imperfect data, methods, and unmodelled chance, while the ceiling itself shows that chance in reproduction alone sets a non-trivial limit on predicting individual lives.
