Controlled study

An experiment or clinical trial in which two groups are used for comparison purpose.

In a controlled exposure study, one group of participants is exposed to a substance (e.g. a pollutant) while those in the "control" group are not. The results are then compared to determine the health effects of the substance being studied.

In a placebo controlled study (often called simply controlled study), people in the "treatment" group are given the drug or treatment being tested while the control group receives a placebo or a different treatment.

Source: GreenFacts

Español: Estudio controlado
Français: Étude contrôlée

PCBs

Climate Change

Ozone

Particulate Matter

Nitrogen Dioxide