A<unk> , also called a<unk> <unk>  comparison, is a<unk>  of participants included in an outcome study that is assigned to a<unk> ing<unk>  and receives intervention after the active treatment<unk> . This<unk><unk>  serves as an untreated comparison<unk>  during the study, but eventually goes on to receive treatment at a later date.<unk> s are often used when it would be unethical to deny participants access to treatment, provided the<unk>  is still shorter than that for routine services.
Wait list control group
Validation therapy
Analysis of clinical trials
Life course approach
In silico clinical trials
Multiple baseline design
Natural history study
Gain-of-function research