Definitions for "Double-blinded"
a clinical trial in which neither the participants nor the doctors know who is receiving the experimental drug and who is receiving the placebo or standard comparison treatments. This method is believed to achieve the most accurate, generalizable results because neither the doctors nor the patients can affect the observed results with their psychological biases.
neither the trial participants nor the researchers know who is receiving which drug or drug dose
A doubled-blinded trial produces more objective and unbiased results because neither the research investigators nor the study participants know who is receiving the investigational drug and who is receiving the placebo