The extent to which a specific health care treatment, service, procedure, program or other intervention does what it is intended to do when used in a community dwelling population is termed its :-
Effectiveness looks at how the intervention works in real-life settings. Efficacy, tests the same in controlled or laboratory settings. Effect modification is all about stratification & occurs when an exposure has a different effect among different subgroups. Effect modification is associated with the outcome but not exposure.
Efficacy
Effectiveness
Effect modification
Efficiency
Disease Causation, Measurements, Milestones