BiasSystematic distortion of the estimated intervention effect away from the "truth", caused by inadequacies in the design, conduct, or analysis of a trial.
Blinding (or Masking)The practice of keeping the trial participants, care providers, those collecting data, and sometimes even those analysing data unaware of which intervention is being administered to which participant. Blinding is intended to prevent bias on the part of study personnel. The most common application is "double-blinding", in which participants, caregivers and those assessing outcome are blinded to intervention assignment. The term "masking" may be used instead of blinding.