Looking forward to presenting The conundrum of twin-singleton differences in intelligence - A centenary (1924-2018), preregistered meta-analysis at the symposium Meta-analyses, meta-meta-analyses, and meta-research in individual differences research! The science of personality and psychological assessment is becoming increasingly collaborative. Researchers in the field now routinely share their hypotheses, data and materials with one another, which enables them to pursue their research questions on a larger scale, in a more co-ordinated manner, and with greater transparency. The 15th biennial DPPD conference will celebrate this and other developments in the spirit of a truly Open Science. Together, we will highlight the progress that has already been made in the field, and identify key issues yet to be resolved. For the first time, the primary conference language at DPPD will be English. Researchers from all over the world are cordially invited to participate and to submit their best work.