Table 4 Recurrent mechanisms reported to explain the different classes of spillovers in the reviewed literature

Within-unit

55

Favourable: 35

Unfavourable: 9

Both: 1

Null: 10

.Learning effects, improvement in overall skills/knowledge/awareness

.Chain response in related behaviours (e.g. physical activity and food intake)

.Complementarity or substitution (in use of inputs or consumption of goods/services) in response to changes in prices or quantities

.Shared resources, complementary activities, shared fixed costs

.Excessively bureaucratised or structured procedures generating changes in others

Diagonal

38

Favourable: 21

Unfavourable: 5

Both: 2

Null: 10

.Complementarity or substitution (in use of inputs or consumption of goods/services) in response to changes in prices or quantities

.Spatial diffusion of the effect (due to ecological mechanisms, proximity, overlapping catchment areas, etc.)

.Shared resources, complementary activities, shared fixed costs

.Social referencing, social learning

.Learning effects, improvement in overall skills/knowledge/awareness

.“Welcome-mat” effect (entering a social protection scheme improves the likelihood of getting access to others through increased knowledge of rules, regulations, availability, etc. for same individuals and family members or friends)

Between-units

36

Favourable: 27

Unfavourable: 4

Both: 1

Null: 4

.Social network effect, social learning, “word of mouth”

.Spatial diffusion of the effect (due to ecological mechanisms, proximity, overlapping catchment areas, etc.)

.Shared resources, complementary activities, shared fixed costs

.“Welcome-mat” effect (entering a social protection scheme improves the likelihood of getting access to others through increased knowledge of rules, regulations, availability, etc. for the same individuals and family members or friends)