HARKing: Hypothesizing After the Results are Known

TLDR

HARKing, the practice of presenting post‑hoc hypotheses as if they were a priori, is a widespread but contentious issue in scientific communication. The article examines why scientists may engage in HARKing and argues against its use. The author proposes suggestions to deter HARKing in order to stimulate discussion. Survey data reveal that multiple forms of HARKing are common and widely viewed as inappropriate.

Abstract

This article considers a practice in scientific communication termed HARKing (Hypothesizing After the Results are Known). HARKing is defined as presenting a post hoc hypothesis (i.e., one based on or informed by one's results) in one's research report as i f it were, in fact, an a priori hypotheses. Several forms of HARKing are identified and survey data are presented that suggests that at least some forms of HARKing are widely practiced and widely seen as inappropriate. I identify several reasons why scientists might HARK. Then I discuss several reasons why scientists ought not to HARK. It is conceded that the question of whether HARKing ' s costs exceed its benefits is a complex one that ought to be addressed through research, open discussion, and debate. To help stimulate such discussion (and for those such as myself who suspect that HARKing's costs do exceed its benefits), I conclude the article with some suggestions for deterring HARKing.