Fig. 1

PRISMA statement of included and excluded studies separated by sustainability and spread/scale. *Generalizability only refers to studies that were only included for mentioning the term “generalizability” and were therefore removed. ⁺Frequent sustainability includes all studies that had sustainability-related text extracted from three or more locations (abstract, introduction etc.). ⁺⁺Occasional sustainability includes all studies that had sustainability-related text extracted from 1 to 2 locations (abstract, introduction etc.). ⁺⁺⁺Frequent spread/scale includes all studies that had spread/scale-related text extracted from two or more locations (abstract, introduction etc.). ⁺⁺⁺⁺Occasional spread/scale includes all studies that had spread/scale-related text extracted from one location (abstract, introduction etc.)