Increasing breast cancer screening uptake: a randomized controlled experiment Léontine Goldzahl * , Guillaume Hollard † Florence Jusot ‡§ Abstract Early screening increases the likelihood of detecting cancer, thereby improving survival rates. National screening programs have been established so that eligible women receive a letter con- taining a voucher for a free screening. Yet, mammography use is often considered as too low. Using a large-scale randomized experiment involving 26,495 women, we test four behavioral in- terventions. Our main assumption is that, because of some biases in their decision process, women may be sensitive to the content and presentation of the invitation letter they received. No treatment had any significant impact on mammography use. Subsample analysis shows that even for women invited for the first time or low income women, treatments had no significant effects. Everything continues as if women are taking clear and well-informed decisions. Policy implications are that existing programs probably reached an upper-bound and can hardly be improved in their current form. Keywords: cancer screening, randomized controlled experiment, behavioral interventions JEL classification: D03; I18 * PSL, Université Paris-Dauphine, Leda-Legos, France. E-mail: leontine.goldzahl@dauphine.fr † CNRS and Ecole Polytechnique, France ‡ PSL, Université Paris-Dauphine, Leda-Legos, France § Acknowledgment: We gratefully acknowledge the financial support of the Ligue Contre le Cancer. The authors would like to thank Pierre-Emmanuel Couralet for his help on data analysis. For the first author, this research has been supported by a post-doctoral grant co-financed by the chair "Santé" at the Fondation du risque and the project ANR 11-LABX-0019 and by the National Institute of Cancer (INCA) 1