Replicating results is one of the cornerstones of science, so why is it so difficult to reproduce a study? In a paper published in Science, collaborators with the Reproducibility Project tried to reproduce the results of 100 psychology studies. The researchers were only able to successfully produce the original results in less than half of the studies. Psychologist Brian Nosek, coordinator of the project, discusses the challenges in reproducing studies, and Leonard Freedman, from the Global Biological Standards Institute, explains the economic cost of irreproducibility in science.