Confounding
A variable that is associated with both the exposure and the outcome, potentially distorting the apparent relationship between them.
In Depth
Confounding is a major challenge in observational cannabis research. Cannabis users differ from non-users in many ways (tobacco use, alcohol use, socioeconomic status, mental health) that independently affect health outcomes. For example, the association between cannabis use and lung cancer is confounded by tobacco co-use. Researchers use statistical methods (multivariable regression, propensity score matching) to control for known confounders, but unmeasured confounding always remains a concern in observational studies.
Related Terms
More in Research Methods
Randomized Controlled Trial (RCT)
The gold standard study design in clinical research. Participants are randomly assigned to treatment or control groups to minimize bias and establish causation.
Systematic Review
A structured synthesis of all available evidence on a specific research question, using predefined criteria to identify, evaluate, and summarize studies.
Meta-Analysis
A statistical technique that combines quantitative data from multiple studies to produce a pooled estimate of effect size with greater statistical power than any individual study.
Placebo-Controlled
A study design in which the control group receives an inert substance (placebo) identical in appearance to the active treatment, to account for the placebo effect.
Observational Study
A study in which researchers observe participants without intervening. Includes cohort studies, case-control studies, and cross-sectional surveys.