In clinical trials, what does a treatment ratio of 1:1 signify?

A treatment ratio of 1:1 in clinical trials signifies that an equal number of participants are assigned to two different treatment groups. This typically involves one group receiving an active treatment, such as a drug, while the other group receives a placebo or an alternative treatment.

The key aspect of a 1:1 ratio is the balanced assignment, meaning there are no biases in the distribution of the participants between the two groups. This is crucial in clinical trials as it helps ensure that the results are statistically valid and that any observed effects can be attributed to the treatment rather than differences in participant characteristics between the groups.

In the context of your answer, it reflects the idea of having an equal number of individuals receiving either the placebo or the active drug, which is foundational in assessing the efficacy and safety of treatments being tested.