Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Blind Procedures02:07

Blind Procedures

10.6K
Ideally, the people who observe and record the children’s behavior are unaware of who was assigned to the experimental or control group, in order to control for experimenter bias. Experimenter bias refers to the possibility that a researcher’s expectations might skew the results of the study. Remember, conducting an experiment requires a lot of planning, and the people involved in the research project have a vested interest in supporting their hypotheses. If the observers knew which...
10.6K
Bias01:22

Bias

3.9K
Bias refers to any tendency that prevents a question from being considered unprejudiced. In research, bias occurs when one outcome or answer is selected or encouraged over others in sampling or testing. Bias can occur during any research phase, including study design, data collection, analysis, and publication.
In statistics, a sampling bias is created when a sample is collected from a population, and some members of the population are not as likely to be chosen as others (remember, each member...
3.9K
Blinding01:11

Blinding

2.4K
Blinding is a commonly used method of not telling participants which treatment a subject is receiving. Blinding is a critical part of a randomized control trial or RCT. It reduces the bias that affects the results. In an RCT, blinding is used in the form of a placebo. A placebo effect occurs when untreated subjects falsely believe they have received the treatment and report improved symptoms. A placebo or a dummy treatment is administered to subjects to negate the bias caused by such an effect.
2.4K
The Placebo Effect01:54

The Placebo Effect

6.1K
The placebo effect occurs when people's expectations or beliefs influence or determine their experience in a given situation. In other words, simply expecting something to happen can actually make it happen.
6.1K
Bias in Epidemiological Studies01:29

Bias in Epidemiological Studies

180
Biases can arise at various stages of research, from study design and data collection to analysis and interpretation. Recognizing and addressing these biases is essential to ensure the validity and reliability of epidemiological findings.Broadly speaking, biases in epidemiology fall into three main categories: selection bias, information bias, and confounding. A more detailed description of possible biases is:  
180
Regression Toward the Mean01:52

Regression Toward the Mean

6.3K
Regression toward the mean (“RTM”) is a phenomenon in which extremely high or low values—for example, and individual’s blood pressure at a particular moment—appear closer to a group’s average upon remeasuring. Although this statistical peculiarity is the result of random error and chance, it has been problematic across various medical, scientific, financial and psychological applications. In particular, RTM, if not taken into account, can interfere when...
6.3K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Viewpoint: are surgeon-scientists still worth the investment?

Annals of medicine and surgery (2012)·2026
Same author

Protein losing enteropathy and hypoalbuminemia after cardiac surgery.

Journal of cardiothoracic surgery·2026
Same author

The Association Between X (Formerly Twitter) Content and Suicide Following a National Media Engagement Strategy in Canada.

Archives of suicide research : official journal of the International Academy for Suicide Research·2026
Same author

Vaccination Vexations.

Journal of general internal medicine·2026
Same author

Discharging patients directly home from an ICU: a FAREWELL checklist approach.

Annals of intensive care·2026
Same author

Development and validation of the Home time and Overall survival after Metastatic spine tumor surgery Estimator (HOME score).

Neuro-oncology advances·2026

Related Experiment Video

Updated: Jun 14, 2025

Inverse Probability of Treatment Weighting Propensity Score using the Military Health System Data Repository and National Death Index
06:55

Inverse Probability of Treatment Weighting Propensity Score using the Military Health System Data Repository and National Death Index

Published on: January 8, 2020

14.4K

Post Hoc Bias in Treatment Decisions.

Donald A Redelmeier1,2,3,4,5, Eldar Shafir6,7

  • 1Department of Medicine, University of Toronto, Toronto, Ontario, Canada.

JAMA Network Open
|September 4, 2024
PubMed
Summary

A small symptom improvement after dubious treatments encourages continued use, even when ineffective. This post hoc bias can lead to complacency and hinder effective healthcare choices.

More Related Videos

Operant Protocols for Assessing the Cost-benefit Analysis During Reinforced Decision Making by Rodents
07:05

Operant Protocols for Assessing the Cost-benefit Analysis During Reinforced Decision Making by Rodents

Published on: September 10, 2018

5.9K
The Joint Effect of Social Comparison and Social Distance on Evaluation of Intertemporal Choice Outcomes in Event-related Potential Studies
08:24

The Joint Effect of Social Comparison and Social Distance on Evaluation of Intertemporal Choice Outcomes in Event-related Potential Studies

Published on: August 25, 2023

656

Related Experiment Videos

Last Updated: Jun 14, 2025

Inverse Probability of Treatment Weighting Propensity Score using the Military Health System Data Repository and National Death Index
06:55

Inverse Probability of Treatment Weighting Propensity Score using the Military Health System Data Repository and National Death Index

Published on: January 8, 2020

14.4K
Operant Protocols for Assessing the Cost-benefit Analysis During Reinforced Decision Making by Rodents
07:05

Operant Protocols for Assessing the Cost-benefit Analysis During Reinforced Decision Making by Rodents

Published on: September 10, 2018

5.9K
The Joint Effect of Social Comparison and Social Distance on Evaluation of Intertemporal Choice Outcomes in Event-related Potential Studies
08:24

The Joint Effect of Social Comparison and Social Distance on Evaluation of Intertemporal Choice Outcomes in Event-related Potential Studies

Published on: August 25, 2023

656

Area of Science:

  • Cognitive psychology
  • Health services research
  • Clinical decision-making

Background:

  • Continuing ineffective treatments can lead to complacency, discourage seeking alternatives, and result in care shortfalls.
  • Understanding biases in treatment continuation is crucial for improving healthcare outcomes.

Purpose of the Study:

  • To investigate the post hoc bias, where marginal symptom improvement after a dubious treatment influences continued use.
  • To assess whether this bias affects both community members and healthcare professionals.

Main Methods:

  • Hypothetical patient scenarios were presented to community members and pharmacists via online and in-person surveys.
  • Respondents were randomized to versions where symptoms marginally improved or remained unchanged after a dubious treatment.
  • The primary outcome measured was the recommendation to continue the treatment.

Main Results:

  • Participants were significantly more likely to recommend continuing dubious treatments (antibiotics, copper bracelet, vitamin B12) when symptoms showed marginal improvement compared to no change.
  • This effect was observed across multiple scenarios and included healthcare professionals.
  • Odds ratios for continuing treatment ranged from 3.98 to 16.19, with P-values < .001.

Conclusions:

  • Marginal symptom improvement following dubious treatments can lead to their continuation, demonstrating a significant post hoc bias.
  • Clinicians should be aware of and caution patients against this bias to prevent the use of ineffective and potentially costly treatments.
  • Addressing this cognitive bias is essential for promoting evidence-based healthcare and preventing care shortfalls.