3 concepts
The Salk Vaccine Field Trial
The Salk polio vaccine field trial incorporated a double blind placebo control methodolgy to determine the effectiveness of the vaccine.
The Portacaval Shunt
Numerous studies have been conducted to examine the value of the portacaval shunt procedure, many using randomized controls.
Statistical Controls
A scientific control is an observation designed to minimize the effects of variables other than the single independent variable.