- The literature search resulted in 782 references, after duplicates were removed
- In total, we identified 12 relevant references: nine describing one intervention and three describing several interventions
- All the studies were from the USA
- The population in the studies were different minority groups (Latinos, Asian Americans, Native Americans, minorities in general)
The interventions were mail, telephone calls, door-to-door canvassing. The messages’ language or rhetorical form was also studied.
We developed a search strategy for a systematic literature search. In September 2015, the search was carried out in social scientific databases. Two researchers independently screened all identified references to assess inclusion according to predefined criteria.