Related Experiment Video
Updated: Mar 11, 2026
05:32
Comparing Eye-tracking Data of Children with High-functioning ASD, Comorbid ADHD, and of a Control Watching Social Videos
Published on: December 7, 2018
9.8K
Comparative Effectiveness Research Using Observational Data: Active Comparators to Emulate Target Trials with
Anders Huitfeldt1, Miguel A Hernan2, Mette Kalager3
1Harvard TH Chan School of Public Health.
EGEMS (Washington, DC)
|November 29, 2016
Summary
Using an active comparator in observational research can emulate trials with inactive comparators, but requires specific conditions to be met. This method may be approximately true, necessitating caution in pharmacoepidemiologic studies.
Area of Science:
- Observational research methodology
- Pharmacoepidemiology
Background:
- Observational studies often use active comparators to avoid confounding by indication.
- This paper explores conditions for emulating trials with inactive comparators using active ones.
Purpose of the Study:
- To define conditions for validly emulating a target trial with an inactive comparator using observational data and an active comparator.
- To assess the plausibility of these conditions in pharmacoepidemiologic research.
Main Methods:
- Discusses conditions for emulating a target trial from observational data.
- Analyzes the validity of using an active comparator when the goal is to emulate a trial with an inactive comparator.
- Evaluates the plausibility of these conditions in pharmacoepidemiologic research, especially with unmeasured confounding.
Main Results:
- Identifies conditions under which an active comparator can emulate a trial with an inactive comparator in specific subpopulations.
- The average treatment effect in the entire population is not identified.
- Conditions may only be approximately true in practice.
Conclusions:
- Active comparator designs can emulate trials with inactive comparators under specific conditions, particularly in subpopulations.
- Caution is advised for investigators using active comparator designs in pharmacoepidemiologic research.
- The plausibility of conditions is questionable in the presence of unmeasured confounding.
Related Concept Videos
01:15Bioequivalence Experimental Study Designs: Repeated Measures, Cross-Over, Carry-Over, and Latin Square Designs
359
Bioequivalence experimental study designs play a pivotal role in testing the effectiveness of various treatments. Key among these are the repeated measures, cross-over, carry-over, and Latin square designs. In the repeated measures design, each subject receives all treatments, allowing for temporal comparisons. This type of design is useful in reducing variability but requires careful planning to avoid bias.The cross-over design, an economical method, involves sequential administration of...
359
01:20Bioequivalence Experimental Study Designs: Completely Randomized and Randomized Block Designs
348
Bioequivalence experimental study designs are crucial methodologies used in evaluating and comparing the bioavailability of different drug products. These designs are categorized into various types: completely randomized, randomized block, repeated measures, cross and carry-over, and Latin square designs.Completely randomized designs involve randomly allocating treatments to all subjects participating in the experiment. This allocation is achieved by assigning unique random numbers to subjects...
348
01:13Randomized Experiments
9.2K
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...
Simple randomization
Simple...
9.2K
01:11Blinding
4.0K
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.
4.0K
01:20Comparing the Survival Analysis of Two or More Groups
682
Survival analysis is a cornerstone of medical research, used to evaluate the time until an event of interest occurs, such as death, disease recurrence, or recovery. Unlike standard statistical methods, survival analysis is particularly adept at handling censored data—instances where the event has not occurred for some participants by the end of the study or remains unobserved. To address these unique challenges, specialized techniques like the Kaplan-Meier estimator, log-rank test, and...
682
01:16Crossover Experiments
4.7K
Crossover experiments, also called the repeated-measurements design, is a study design in which all experimental units are exposed to all treatments in different periods. Crossover experiments are generally used in psychology, the pharmaceutical industry, agriculture, and medicine.
Crossover designs are performed even with smaller sample sizes since the samples can act as their controls. These are better than simple randomized trials since patients are exposed to all the treatments.
Crossover designs are performed even with smaller sample sizes since the samples can act as their controls. These are better than simple randomized trials since patients are exposed to all the treatments.
4.7K