Jensen 2014.

Study characteristics
Methods	Controlled before‐after study
Participants	General practitioners
Interventions	Denmark Intervention: mixed system of capitation and FFS contracts. GPs in Copenhagen moved from pure capitation to a mix of one‐third capitation and two‐thirds FFS contracts. Control: pure capitation contracts Years 1984 to 1988, intervention happened in 1987
Outcomes	Patient outcomes Birth weight: 1.0% lower under the capitation system, P > 0.05 Low birth weight: no difference Preterm birth: infants have a 1.9 percentage point (36.5% from the base of 5.2% births) Higher probability of preterm birth Very preterm birth: no difference Fetal growth: infants born under capitation contracts have 0.8 g per week
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	The allocation is not made by the investigator.
Allocation concealment (selection bias)	Unclear risk	The allocation is not made by the investigator.
Baseline outcome measurements similar	Unclear risk	No more information in text
Baseline characteristics similar	Low risk	The baseline characteristics are not similar, but the results changed only marginally when the author excluded these variables from the model.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No more information in text
Knowledge of the allocated interventions adequately prevented	Low risk	The outcomes are objective.
Study adequately protected against contamination	Low risk	Children are automatically assigned to their mother’s GP, and the possibility of reallocation within a municipality without moving occurs only annually.
Selective reporting (reporting bias)	Low risk	The outcomes mentioned in the methods were reported in the results.
Other bias	Low risk	No more information in text