Comparison groups should be treated equally

This is the sixteenth blog in a series of 34 blogs explaining 34 key concepts we need to be able to understand to think critically about treatment claims.

Apart from the treatments being compared, people in the treatment comparison groups should otherwise receive similar care. If, for example, people in one group receive more attention and care than people in the comparison group, differences in outcomes could be due to differences in the amount of attention each group received rather than due to the treatments that are being compared. One way of preventing this is to keep providers unaware (“blind”) of which people have been allocated to which treatment.