This is because there is nothing wrong with constructing hypotheses after examining results after all, many important discoveries in science were serendipitously made after, not before, generating and inspecting data. The italicized part of the definition constitutes the QRP in HARKing. HARKing means “Hypothesizing After the Results are Known.” 1–3 HARKing is a QRP wherein a researcher analyzes data, observes a (not necessarily expected) statistically significant result, constructs a hypothesis based on that result, and then presents the result and the hypothesis as though the study had been designed, conducted, and analyzed or at least oriented to test that hypothesis. This article uses examples to briefly present and explain certain of such questionable research practices (QRPs). In psychiatry and in psychopharmacology, as in other branches of medicine, researchers may knowingly or unknowingly violate scientific principles when analyzing their data and, afterward, when communicating their results in their research papers to the scientific community. This knowledge must become widespread so that researchers and readers understand what approaches to statistical analysis and reporting amount to scientific misconduct.

This article explains what these QRPs are and why they are QRPs. Data dredging and data mining describe the extensive testing of relationships between a large number of variables for which data are available, usually in a database. A fishing expedition is the indiscriminate testing of associations between different combinations of variables not with specific hypotheses in mind but with the hope of finding something that is statistically significant in the data. P-hacking is the relentless analysis of data with an intent to obtain a statistically significant result, usually to support the researcher’s hypothesis. Cherry-picking is the presentation of favorable evidence with the concealment of unfavorable evidence. HARKing (Hypothesizing After the Results are Known) is the presentation of a post hoc hypothesis as an a priori hypothesis. Questionable research practices (QRPs) in the statistical analysis of data and in the presentation of the results in research papers include HARKing, cherry-picking, P-hacking, fishing, and data dredging or mining.

Dredging mining data