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

Randomized Experiments01:13

Randomized Experiments

9.4K
The randomization process involves assigning study participants randomly to experimental or control groups based on their probability of being equally assigned. Randomization is meant to eliminate selection bias and balance known and unknown confounding factors so that the control group is similar to the treatment group as much as possible. A computer program and a random number generator can be used to assign participants to groups in a way that minimizes bias.
Simple randomization
Simple...
9.4K
Sign Test for Matched Pairs01:17

Sign Test for Matched Pairs

483
The sign test for matched pairs offers a robust method for comparing two paired samples, often for the effects of an intervention in one of them. This method is very useful in situations where the underlying distribution of the data is unknown. The test compares two related samples—often pre- and post-treatment measurements on the same subjects—to determine if there are significant differences in their median values.
To conduct the sign test, we first calculate the differences in...
483
Wilcoxon Signed-Ranks Test for Matched Pairs01:09

Wilcoxon Signed-Ranks Test for Matched Pairs

638
The Wilcoxon signed-rank test for matched pairs evaluates the null hypothesis by combining the ranks of differences with their signs. It essentially tests whether the median of the differences in a population of matched pairs is zero. Since the test incorporates more information than the sign test, it generally yields more trustable conclusions. This test also does not require the data to follow a normal distribution, but two conditions must be met for it to be applicable: (1) the data must...
638
Group Design02:01

Group Design

11.1K
The most basic experimental design involves two groups: the experimental group and the control group. The two groups are designed to be the same except for one difference— experimental manipulation. The experimental group gets the experimental manipulation—that is, the treatment or variable being tested—and the control group does not. Since experimental manipulation is the only difference between the experimental and control groups, we can be sure that any differences between...
11.1K
Random Sampling Method01:09

Random Sampling Method

16.0K
Sampling is a technique to select a portion (or subset) of the larger population and study that portion (the sample) to gain information about the population. Data are the result of sampling from a population. The sampling method ensures that samples are drawn without bias and accurately represent the population. Because measuring the entire population in a study is not practical, researchers use samples to represent the population of interest. Among the various sampling methods used by...
16.0K
Strategies for Assessing and Addressing Confounding01:25

Strategies for Assessing and Addressing Confounding

580
Confounding is a critical issue in epidemiological studies, often leading to misleading conclusions about associations between exposures and outcomes. It occurs when the relationship between the exposure and the outcome is mixed with the effects of other factors that influence the outcome. Given that, addressing confounding is of high importance for drawing accurate inferences in research.
Confounding can be addressed at both the design phase of a study and through analytical methods after data...
580

You might also read

Related Articles

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

Sort by
Same author

Interferon-Gamma Release Assays versus Tuberculin Skin Test for latent tuberculosis infection positivity among healthcare workers and first responders: a systematic review and meta-analysis.

International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases·2026
Same author

Implementing gestational weight gain guidelines in midwifery practice: A qualitative study using Normalisation Process Theory.

Midwifery·2026
Same author

Region of Employment and Intention to Remain Practicing or Exit the Profession Among Australian Nurses: A Cross-Sectional Analysis.

Journal of nursing management·2026
Same author

Economic Impact of Diabetes: Estimating the Incremental Costs of Diabetes-Related Complications in Western Australia Using Linked Administrative Data.

Value in health regional issues·2026
Same author

Region of Employment and Intention to Remain Practicing or Exit the Profession Among Australian Nurses: A Cross-Sectional Analysis.

Journal of nursing management·2026
Same author

Randomized Controlled Trial on the Impact of Befriending on Depression, Anxiety, Loneliness, and Social Support in Older People in Aged Care.

Clinical gerontologist·2025
Same journal

Harms Reporting Was Frequently Incomplete or Discordant in Biomedical Randomized Trials Published in 2023: A Meta-epidemiological Study.

Journal of clinical epidemiology·2026
Same journal

Using an Open Science Checklist in Grant Proposal Reviews to Predict Reproducibility of Funded Publications.

Journal of clinical epidemiology·2026
Same journal

A comparison of five statistical methods used to analyse longitudinal EORTC QLQ-C30 quality of life scores in randomised controlled trials: a simulation study.

Journal of clinical epidemiology·2026
Same journal

Sample Size Determination for Decision-centered Pragmatic Trials.

Journal of clinical epidemiology·2026
Same journal

Many multicenter randomized controlled trials do not account for center effect: a methodological review.

Journal of clinical epidemiology·2026
Same journal

Patient Acceptability of the Modified Zelen Approach to Randomized Trials - A Survey of the CAPS THA Cohort.

Journal of clinical epidemiology·2026
See all related articles

Related Experiment Video

Updated: Apr 17, 2026

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

15.5K

Propensity score matching and randomization.

George Mnatzaganian1, David C Davidson2, Janet E Hiller3

  • 1School of Allied Health, Faculty of Health Sciences, Australian Catholic University, Level 2, Daniel Mannix Building, 17 Young Street, Fitzroy, Victoria 3065, Australia.

Journal of Clinical Epidemiology
|February 10, 2015
PubMed
Summary
This summary is machine-generated.

Elective total joint replacement (TJR) selection favors younger, healthier patients, introducing bias. This highlights the need for caution when comparing long-term outcomes between surgical and non-surgical groups.

Keywords:
Channeling biasConfoundingElective total joint arthroplastyInternal and external validityPropensity score matchingRandomizationSelection bias

More Related Videos

Influence of Emotional Factors on the Efficacy of Acupuncture Treatment for Overweight Complicated with Hyperlipidemia: A Retrospective Cohort Study
03:05

Influence of Emotional Factors on the Efficacy of Acupuncture Treatment for Overweight Complicated with Hyperlipidemia: A Retrospective Cohort Study

Published on: November 21, 2025

810
A Psychophysics Paradigm for the Collection and Analysis of Similarity Judgments
08:12

A Psychophysics Paradigm for the Collection and Analysis of Similarity Judgments

Published on: March 1, 2022

3.1K

Related Experiment Videos

Last Updated: Apr 17, 2026

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

15.5K
Influence of Emotional Factors on the Efficacy of Acupuncture Treatment for Overweight Complicated with Hyperlipidemia: A Retrospective Cohort Study
03:05

Influence of Emotional Factors on the Efficacy of Acupuncture Treatment for Overweight Complicated with Hyperlipidemia: A Retrospective Cohort Study

Published on: November 21, 2025

810
A Psychophysics Paradigm for the Collection and Analysis of Similarity Judgments
08:12

A Psychophysics Paradigm for the Collection and Analysis of Similarity Judgments

Published on: March 1, 2022

3.1K

Area of Science:

  • Orthopedic Surgery
  • Biostatistics
  • Health Services Research

Background:

  • Elective total joint replacement (TJR) is a common procedure.
  • Patient selection for TJR may introduce bias.
  • Understanding selection bias is crucial for accurate outcome assessment.

Purpose of the Study:

  • To demonstrate selection bias in elective total joint replacement (TJR).
  • To assess the impact of patient selection on outcome comparisons.

Main Methods:

  • Utilized longitudinal data from 2,202 men (1996-2007).
  • Constructed propensity scores (PS) to match TJR recipients with non-recipients.
  • Compared 10-year mortality between matched cases and controls.

Main Results:

  • 37.2% of participants underwent TJR.
  • TJR patients were younger, healthier, and of higher socioeconomic status.
  • Controls had significantly higher 10-year mortality (39.5%) compared to TJR cases (14.5%).

Conclusions:

  • Selection for elective procedures can introduce bias not fully captured by PS matching.
  • Caution is advised when comparing long-term outcomes between surgical and non-surgical groups.
  • Further research needed to mitigate selection bias in outcome studies.