How does an Active Control group help mitigate the Hawthorne effect?

Answer

Both the experimental and active control groups are equally aware of being observed.

Since the Hawthorne effect stems from awareness of observation, having both groups aware—one receiving the new intervention and the other receiving the standard treatment—allows researchers to isolate the mechanism of the *new* intervention specifically.

How does an Active Control group help mitigate the Hawthorne effect?
experimentconclusionresearchmethodologycontrol group