Pre-registering research in Child Development: Why, when, what, and how. Anna E. van ‘t Veer1, Roger Giner-Sorolla2, Christiane J. A. Luttikhuizen1, Marian J. Bakermans-Kranenburg1 & Marinus H. van IJzendoorn1 1Child and Family Studies, Leiden University, 2School of Psychology, University of Kent a.e.van.t.veer@fsw.leidenuniv.nl Pre-registration: Why? Pre-registration: What? Pre-registration: How? Online services for pre-registration: Open Science Framework (https://cos.io) AsPredicted.org Socialscienceregistry.org (ClinicalTrials.gov) Journals offering pre-registration**: Infancy Journals requiring or advising trial registration in a public registry before or at the time of first patient enrolment**: Journal of the American Academy of Child and Adolescent Psychiatry; Journal of Child Psychology and Psychiatry; Developmental Neuroscience; Attachment and Human Development; Frontiers in Developmental Psychology; European Journal of Developmental Psychology; Autism. Journals advising trial registration and/or open data/methods after publication**: Psychoneuroendocrinology; Developmental Cognitive Neuroscience; Journal of Adolescent Health; Child Development; Developmental Medicine and Child Neurology; Developmental Biology; Child Abuse & Neglect; Journal of Experimental Child Psychology; Child and Adolescent Psychiatry and Mental Health; Early Childhood Research Quarterly; International Journal of Behavioral Development; Journal of Applied Developmental Psychology. In the past years many authors, granting agencies, and journal editors in social and behavioral sciences have taken note of problems with publication bias and reproducibility, and are considering pre-registration of research as part of the solution. However, a full-text search in 79 central journals in Child Development research* revealed that none of the hundreds of thousands of papers searched mentions that the research is pre-registered**. We call for the adaption of this practice for these reasons: Pros. Pre-registration enhances confidence in findings by1-5: increasing transparency separating confirmatory from exploratory research emphasizing theory and methods reducing reporting and publication bias, incentivizing an overall shift from quantity to quality giving In Principle Acceptance (IPA); results are published no matter the outcome. Cons. Time and effort are required for writing and reviewing the plan by the researcher and reviewer, respectively. Researchers describe their hypotheses, methods, and analyses before conducting their study. A link to the timestamped plans can be included in a manuscript (see Figure 1 for a research flow). Several pre-registration formats are available, some merely ask for the hypotheses to be registered. Researchers can choose the format that fits their needs and/or the requirements of a specific journal. For suggestions on what to include in the pre-registration, see van ‘t Veer & Giner-Sorolla (2016). Figure 1. In return for their time and effort put into a pre-registration, researchers gain confidence in their findings timely input from reviewers enhancing quality of the research. Additional advantages: decreased chance of rejection reduction of overall reviewer time due to reduction of number of journals a paper sees before it gets accepted. See Figure 1: thicker arrows at the bottom indicate bigger chances More information *Journals comprised of 69 journals placed by Web of Science in the category ‘Psychology, Developmental’, and 10 additional journals also related to Child Development. **Data and methods, as well as this poster and Figure 1, can be found here: https://osf.io/cky48/files/ References 1 Chambers, C. D., Feredoes, E., Muthukumaraswamy, S. D., & Etchells, P. J. (2014). Instead of “playing the game” it is time to change the rules: Registered reports at AIMS Neuroscience and beyond. AIMS Neuroscience, 1(1), 4–17. 2 LeBel, E. P., & Peters, K. R. (2011). Fearing the future of empirical psychology: Bem's (2011) evidence of psi as a case study of deficiencies in modal research practice. Review of General Psychology, 15(4), 371–379. 3 Murayama, K., Pekrun, R., & Fiedler, K. (2013). Research practices that can prevent an inflation of false-positive rates. Personality and Social Psychology Review, 18(2), 107–118. 4 van 't Veer, A. E., & Giner-Sorolla, R. (2016). Pre-registration in social psychology—A discussion and suggested template. Journal of Experimental Social Psychology, 67, 2-12. 5 Wagenmakers, E. -J., Wetzels, R., Borsboom, D., van der Maas, H. L. J., & Kievit, R. A. (2012). An agenda for purely confirmatory research. Perspectives on Psychological Science, 7(6), 632–638. Pre-registration: When? Once researchers have formed their hypotheses they can pre-register them. This separates a phase of exploration (data is used to generate hypotheses) from confirmation (new data is used to confirm hypotheses). Exploration of new data can still occur, but is labeled as such in the paper.