Reproducibility: Seek out stronger science

When graduate student Alyssa Ward took a science-policy internship, she expected to learn about policy — not to unearth gaps in her biomedical training. She was compiling a bibliography about the reproducibility of experiments, and one of the papers, a meta-analysis, found that scientists routinely fail to explain how they choose the number of samples to use in a study. "My surprise was not about the omission — it was because I had no clue how, or when, to calculate sample size," Ward says. Nor had she ever been taught about major categories of experimental design, or the limitations of P values. (Although they can help to judge the strength of scientific evidence, P values do not — as many think — estimate the likelihood that a hypothesis is true.)