Overview on the Null Hypothesis Significance Test

For decades, waxing and waning, there has been an ongoing debate on the values and problems of the ubiquitously used null hypothesis significance test (NHST). With the start of the replication crisis, this debate has flared-up once again, especially in the psychology and psychological methods literature. Arguing for or against the NHST method usually takes place in essays and opinion pieces that cover some, but not all the qualities and problems of the method. The NHST literature landscape is vast, a clear overview is lacking, and participants in the debate seem to be talking past one another. To contribute to a resolution, we conducted a systematic review on essay literature concerning NHST published in psychology and psychological methods journals between 2011 and 2018. We extracted all arguments in defense of (20) and against (70) NHST, and we extracted the solutions (33) that were proposed to remedy (some of) the perceived problems of NHST. Unfiltered, these 123 items form a landscape that is prohibitively difficult to keep in one’s sights. Our contribution to the resolution of the NHST debate is twofold. 1) We performed a thematic synthesis of the arguments and solutions, which carves the landscape in a framework of three zones: mild, moderate, and critical. This reduction summarizes groups of arguments and solutions, thus offering a manageable overview of NHST’s qualities, problems, and solutions. 2) We provide the data on the arguments and solutions as a resource for those who will carry-on the debate and/or study the use of NHST.