Replication Crisis? What Replication Crisis?
[Excerpts taken from the article “No Crisis but No Time for Complacency” by Wendy Wood and Timothy Wilson, published in Observer Magazine]
“The National Academies of Sciences, Engineering, and Medicine recently published a report titled Reproducibility and Replicability in Science. We both had the privilege of serving on the committee that issued the report, and this is a brief summary of how the committee came about and its main findings.”
“In response to concerns about replicability in many branches of science, Congress — via the National Science Foundation — directed the National Academies to conduct a study. The mandate was broad: to define reproducibility and replicability, assess what is known about how science is doing in these areas, review current attempts to improve reproducibility and replicability, and make recommendations for improving rigor and transparency in research — across all fields of science and engineering…”
“So, what did the committee conclude? Our job was first to define reproducibility and replicability…We defined reproducibility as computational reproducibility — obtaining consistent computational results using the same input data, computational steps, methods, code, and conditions of analysis. Replicability was defined as obtaining consistent results across studies that were aimed at answering the same scientific question, each of which obtained its own data. In short, reproducing research involves using the original data and code, whereas replicating research involves new data collection and methods similar to those used in previous studies.”
“Once we defined our terms, what did the committee conclude about the state of reproducibility and replicability in science?…The committee’s answer was, in short, ‘No crisis, but no complacency.’”
“We saw no evidence of a crisis, largely because the evidence of nonreproducibility and nonreplicability across all science and engineering is incomplete and difficult to assess.”
“…a key observation in the report, we believe, is that, “The goal of science is not, and ought not to be, for all results to be replicable” (p. 28), because there is a tension between replicability and discovery.”
“…the committee noted that nonreplicability can arise from a number of sources, some of which are potentially helpful to advancing scientific knowledge and others that are unhelpful.”
“Nonreplicability can be caused by limits in current scientific knowledge and technologies, as well as inherent but uncharacterized variabilities in the system being studied. When such nonreplicating results are investigated and resolved, it can lead to new insights, better characterization of uncertainties, and increased knowledge about the systems being studied and the methods used to study them.”
“Nonreplicability also may be due to foreseeable shortcomings in the design, conduct, and communication of a study. Whether arising from lack of understanding, perverse incentives, sloppiness, or bias, these unhelpful sources of nonreplicability reduce the efficiency of scientific progress.”
“Replicability and reproducibility are not the only ways to gain confidence in scientific results. Research synthesis and meta-analysis can help assess the reliability and validity of bodies of research…Meta-analytic tests for variation in effect sizes can suggest potential causes of nonreplicability in existing research — in individual studies that are outliers, in particular populations, or using certain methods. Of course, such analyses must take into account the possibility that published results are biased by selective reporting and, to the extent possible, estimate its effects.”
“We strongly endorse the broad conclusion from our meetings: No crisis, but no time for complacency!”
To read the article, click here.