P-value: Difference between revisions

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A '''<i>p</i> value''' is a value calculated from a research study, which is intended to show whether an outcome is likely to have occurred by chance, when taking into consideration a number of other factors.<ref>{{Cite web|url=https://medical-dictionary.thefreedictionary.com/p+value| title = Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health|website=TheFreeDictionary.com|access-date=2019-04-21 | date = | last =  | first = |authorlink=|archive-date=|url-status=| year = 2003|editor-last=|edition=7th|archive-url=}}</ref><ref>{{Cite web|url=https://www.merriam-webster.com/dictionary/P+value| title = Definition of P VALUE | last = Merrian-Webster Dictionary | first = |authorlink=| date = |website=Merrian-Webster Dictionary|language=en|archive-url=|archive-date=|url-status=|access-date=2019-04-21}}</ref> ''P'' values are not actually defined as a probability.<ref name=":0">{{Cite journal | last = Kuffner | first = Todd A. | authorlink= | last2 = Walker |  first2 = Stephen G. | date=Jan 2, 2019| title = Why are p-Values Controversial?|url=https://doi.org/10.1080/00031305.2016.1277161|journal=The American Statistician|volume=73|issue=1|pages=1–3|doi=10.1080/00031305.2016.1277161|issn=0003-1305|quote=|via=}}</ref> '''<i>P</i>-hacking''' is the manipulation of research data to produce a clinically significant result for the calculated <i>p</i> value; meaning manipulating research results in order to achieve '''''p < 0.05''''' rather than publishing a [[null result]].{{citation needed}}
A '''<i>p</i> value''' is a value calculated from a research study, which is intended to show whether an outcome is likely to have occurred by chance, when taking into consideration a number of other factors.<ref>{{Cite web|url=https://medical-dictionary.thefreedictionary.com/p+value| title = Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health|website=TheFreeDictionary.com|access-date=2019-04-21 | date = | last =  | first = | authorlink = |archive-date=|url-status=| year = 2003|editor-last=|edition=7th|archive-url=}}</ref><ref>{{Cite web|url=https://www.merriam-webster.com/dictionary/P+value| title = Definition of P VALUE | last = Merrian-Webster Dictionary | first = | authorlink = | date = |website=Merrian-Webster Dictionary|language=en|archive-url=|archive-date=|url-status=|access-date=2019-04-21}}</ref> ''P'' values are not actually defined as a probability.<ref name=":0">{{Cite journal | last = Kuffner | first = Todd A. | authorlink= | last2 = Walker |  first2 = Stephen G. | date=Jan 2, 2019| title = Why are p-Values Controversial?|url=https://doi.org/10.1080/00031305.2016.1277161|journal=The American Statistician|volume=73|issue=1|pages=1–3|doi=10.1080/00031305.2016.1277161|issn=0003-1305|quote=|via=}}</ref> '''<i>P</i>-hacking''' is the manipulation of research data to produce a clinically significant result for the calculated <i>p</i> value; meaning manipulating research results in order to achieve '''''p < 0.05''''' rather than publishing a [[null result]].{{citation needed}}


==Theory==
==Theory==

Revision as of 03:32, March 4, 2023

A p value is a value calculated from a research study, which is intended to show whether an outcome is likely to have occurred by chance, when taking into consideration a number of other factors.[1][2] P values are not actually defined as a probability.[3] P-hacking is the manipulation of research data to produce a clinically significant result for the calculated p value; meaning manipulating research results in order to achieve p < 0.05 rather than publishing a null result.[citation needed]

Theory

Evidence

Null hypothesis significance testing

Articles and blogs

Notable studies

  • 2012, A peculiar prevalence of p values just below .05[4] (Abstract)
  • 2013, The life of p: “Just significant” results are on the rise[5] (Abstract)
  • 2015, Blinded by the Light: How a Focus on Statistical “Significance” May Cause p-Value Misreporting and an Excess of p-Values Just Below .05 in Communication Science[7] (Full text)
  • 2016, Degrees of Freedom in Planning, Running, Analyzing, and Reporting Psychological Studies: A Checklist to Avoid p-Hacking[8] (Full text)

See also

Learn more

References

  1. ↑ "Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health". TheFreeDictionary.com (7th ed.). 2003. Retrieved April 21, 2019.
  2. ↑ Merrian-Webster Dictionary. "Definition of P VALUE". Merrian-Webster Dictionary. Retrieved April 21, 2019.
  3. ↑ 3.0 3.1 Kuffner, Todd A.; Walker, Stephen G. (January 2, 2019). "Why are p-Values Controversial?". The American Statistician. 73 (1): 1–3. doi:10.1080/00031305.2016.1277161. ISSN 0003-1305.
  4. ↑ Masicampo, E.J.; Lalande, Daniel R. (November 2012). "A peculiar prevalence of p values just below .05". Quarterly Journal of Experimental Psychology. 65 (11): 2271–2279. doi:10.1080/17470218.2012.711335. ISSN 1747-0218.
  5. ↑ Leggett, Nathan C.; Thomas, Nicole A.; Loetscher, Tobias; Nicholls, Michael E.R. (December 1, 2013). "The life of p: "Just significant" results are on the rise". The Quarterly Journal of Experimental Psychology. 66 (12): 2303–2309. doi:10.1080/17470218.2013.863371. ISSN 1747-0218. PMID 24205936.
  6. ↑ Lakens, Daniël (April 1, 2015). "Comment: What p-hacking really looks like: A comment on Masicampo and LaLande (2012)". Quarterly Journal of Experimental Psychology. 68 (4): 829–832. doi:10.1080/17470218.2014.982664. ISSN 1747-0218.
  7. ↑ Vermeulen, Ivar; Beukeboom, Camiel J.; Batenburg, Anika; Avramiea, Arthur; Stoyanov, Dimo; van de Velde, Bob; Oegema, Dirk (October 2, 2015). "Blinded by the Light: How a Focus on Statistical "Significance" May Cause p-Value Misreporting and an Excess of p-Values Just Below .05 in Communication Science". Communication Methods and Measures. 9 (4): 253–279. doi:10.1080/19312458.2015.1096333. ISSN 1931-2458.
  8. ↑ van Assen, Marcel A. L.M.; van Aert, Robbie C.M.; Bakker, Marjan; Augusteijn, Hilde E.M.; Veldkamp, Coosje L.S.; Wicherts, Jelte M. (2016). "Degrees of Freedom in Planning, Running, Analyzing, and Reporting Psychological Studies: A Checklist to Avoid p-Hacking". Frontiers in Psychology. 7. doi:10.3389/fpsyg.2016.01832. ISSN 1664-1078. Cite has empty unknown parameter: |authorlinklink5= (help)
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