Reproducibility and Replicability in a Fast-paced Methodological World

Methodological developments and software implementations progress in increasingly faster time-frames. The introduction and widespread acceptance of pre-print archived reports and open-source software make state-of-the-art statistical methods readily accessible to researchers. At the same time, researchers more and more emphasize that their results should be reproducible (using the same data obtaining the same results), which is a basic requirement for assessing the replicability (obtaining similar results in new data) of results. While the age of fast-paced methodology greatly facilitates reproducibility, it also undermines it in ways not often realized by researchers. The goal of this paper is to make researchers aware of these caveats. I discuss sources of limited replicability and reproducibility in both the development of novel statistical methods and their implementation in software routines. Novel methodology comes with many researcher degrees of freedom, and new understanding comes with changing standards over time. In software-development, reproducibility may be impacted due to software developing and changing over time, a problem that is greatly magnified by large dependency-trees between software-packages. The paper concludes with a list of recommendations for both developers and users of new methods to improve reproducibility of results.