Resources

In this course, we will explore the so‐called “reproducibility crisis” that has struck fields from psychology and economics to ecology and cancer biology. You will learn statistical principles at the heart of the reproducibility crisis, how disregard …

When designing a study, the planned sample size is often based on power analyses. One way to choose an effect size for power analyses is by relying on pilot data. A-priori power analyses are only accurate when the effect size estimate is accurate. In …

This paper explains how to select the correct statistical test for a research project, clinical trial, or other investigation. The first step is to decide in what scale of measurement your data are as this will affect your decision—nominal, ordinal, …

Open data is receiving increased attention and support in academic environments, with one justification being that shared data may be re-used in further research. But what evidence exists for such re-use, and what is the relationship between the …

About two months ago, I published an interview with Richard Poynder in which he discussed his recent announcement that he was “signing off from reporting on open access,” because “the movement has failed and is being rebranded in order to obscure the …

A video about psychology being trouble

We describe what is a pre-analysis plan (PAP) and why you should use one. We emphasize the potential political uses of PAPs and, in particular, how the PAP is in this respect a uniquely powerful tool for increasing the likelihood that evidence …

For almost half a century, Paul Meehl educated psychologists about how the mindless use of null-hypothesis significance tests made research on theories in the social sciences basically uninterpretable. In response to the replication crisis, reforms …

Newly discovered true (non-null) associations often have inflated effects compared with the true effect sizes. I discuss here the main reasons for this inflation. First, theoretical considerations prove that when true discovery is claimed based on …

Low power in experimental psychology is an oft-discussed problem. We show in the context of the Replicability Project: Psychology (Open Science Collaboration, 2015) that sample sizes are so small in psychology that often one cannot detect even large …