Questionable research practices (QRPs) pose a significant threat to the quality of scientific research. However, historically, they remain ill-defined, and a comprehensive list of QRPs is lacking. In this article, we address this concern by defining, collecting, and categorizing QRPs using a community-consensus method. Collaborators of the study agreed on the following definition: QRPs are ways of producing, maintaining, sharing, analyzing, or interpreting data that are likely to produce misleading conclusions, typically in the interest of the researcher. QRPs are not normally considered to include research practices that are prohibited or proscribed in the researcher’s field (e.g., fraud, research misconduct). Neither do they include random researcher error (e.g., accidental data loss). Drawing from both iterative discussions and existing literature, we collected, defined, and categorized 40 QRPs for quantitative research. We also considered attributes such as potential harms, detectability, clues, and preventive measures for each QRP. The results suggest that QRPs are pervasive and versatile and have the potential to undermine all stages of the scientific enterprise. This work contributes to the maintenance of research integrity, transparency, and reliability by raising awareness for and improving the understanding of QRPs in quantitative psychological research.
