Compared to a more standard experimental design which would assign observations to a control group or a treatment group, a synthetic cohort analysis

Multiple Cholce

only has a control group.

uses a sophisticated algorithm to estimate data for observations in the control group.

finds other populations that "mirror" the treatment group in many ways in order to argue that these other populations can serve as a valid control group.

assigns observations to the control or treatment group based on certain demographics such as location or race.

only has a treatment group.