Post hoc analysis

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In a scientific study, post hoc analysis (from Latin post hoc, "after this") consists of statistical analyses that were specified after the data were seen.[1][2] They are usually used to uncover specific differences between three or more group means when an analysis of variance (ANOVA) test is significant.[3] This typically creates a multiple testing problem because each potential analysis is effectively a statistical test. Multiple testing procedures are sometimes used to compensate, but that is often difficult or impossible to do precisely. Post hoc analysis that is conducted and interpreted without adequate consideration of this problem is sometimes called data dredging by critics because the statistical associations that it finds are often spurious. [4]

Common post hoc tests[edit]

Some common post hoc tests include: [5][6]


Sometimes the temptation to engage in post hoc analysis is motivated by a desire to produce positive results or see a project as successful. In the case of pharmaceutical research, there may be significant financial consequences to a failed trial.

See also[edit]


  1. ^ "What is the significance and use of post-hoc analysis studies?". Retrieved 2022-12-09.
  2. ^ "11.8: Post Hoc Tests". Statistics LibreTexts. 2019-11-12. Retrieved 2022-12-09.
  3. ^ "SAGE Research Methods - The SAGE Encyclopedia of Communication Research Methods". Retrieved 2022-12-09.
  4. ^ Zhang, Yiran; Hedo, Rita; Rivera, Anna; Rull, Rudolph; Richardson, Sabrina; Tu, Xin M. (2019-08-01). "Post hoc power analysis: is it an informative and meaningful analysis?". General Psychiatry. 32 (4): e100069. doi:10.1136/gpsych-2019-100069. ISSN 2517-729X. PMC 6738696.
  5. ^ "Post Hoc Definition and Types of Tests". Statistics How To. Retrieved 2022-12-09.
  6. ^ Pamplona, Fabricio (2022-07-28). "Post Hoc Analysis: Process and types of tests". Mind the Graph Blog. Retrieved 2022-12-09.