2. Payment methods for the vulnerable populations.

Target population	Payment methods	Outcomes
The elderly	Not reported in included studies	Not reported in included studies
The disabled	Not reported in included studies	Not reported in included studies
Minorities	Not reported in included studies	Not reported in included studies
People with low levels of education	Not reported in included studies	Not reported in included studies
Children
Clarkson 2008, cluster‐randomised trial	FFS remuneration	Children with 1 or more sealant per dentist
Davidson 1992, randomised trial	Capitation, FFS high rate compare with FFS (low rates)	Physician visits, hospitalisations
Jensen 2014, controlled before‐after study	Mixed system of capitation and FFS contracts	Birth weight, preterm birth, very preterm birth, fetal growth
Singh 2015, controlled before‐after study	Performance bonus	Weight, WHO malnourished status
Women
Bilardi 2010, cluster randomised trial	P4P (a small incentive payment per test)	Women being tested
People living in rural or remote areas
Yesalis 1980; Yesalis 1984, controlled before‐after study	Capitation compare with FFS	Rate of generic substitution per 100 prescriptions Percentage of Medicaid prescriptions classified as multi‐source drug products Numbers of prescriptions involving changes in labeller on refills (0 to 5 days)
Low‐income populations 2
Christensen 2000, randomised trial, Medicaid recipients	Financial incentive (P4P)	Patients receiving cognitive services
Gleeson 2017, controlled before‐after study, Medicaid	P4P plus existing FFS compare with FFS	Adolescent well care, inactivated polio vaccine

FFS: fee‐for‐service
P4P: pay for performance
WHO: World Health Organization