(OB-ser-VAY-shuh-nul STUH-dee) 
A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given).
(OB-ser-VAY-shuh-nul STUH-dee)
A type of study in which individuals are observed or certain outcomes are measured. No attempt is made to affect the outcome (for example, no treatment is given).