Study	Reason for exclusion
Abelsen 2015	This is a cross‐sectional study.
Agee 2014	Just a comparative study
Allard 2014	This study just used a model of physician treatment and referral decisions under endogenous payment form in the flavour of Allard and colleagues.
Allen 2016	Not a Controlled before‐after study (CBA) study design: although it uses difference‐in‐differences model, study lacks a control group
Alshamsan 2012	The provider is institution.
An 2008	Study participants are clinics.
Arrowsmith 2014	The provider is institution.
Baker 2005	This study is not an Randomised Controlled Trial (RCT), CBA, or Interrupted Time Series (ITS).
Barnato 2017	The target of the intervention in this study is the patient.
Basu 2016	The outcome index concerns the impact on financial outcome.
Boyden 2000	The provider is institution.
Broadway 2017	This study is not an RCT, CBA, or ITS; it uses a structure, discrete choice model.
Carey 1990	Not control study
Chen 2016	Not a CBA study design; control group was created by matching methods to conduct difference‐in‐differences analysis
Clancy 1988	Not control study
Coleman 2007	Not a CBA study, only a before‐and‐after study
Davies 1986	Provider is insurance plan.
Douven 2015	Not an ITS study design because it does not have a clearly defined point in time; only time trends are described
Engineer 2016	The participants of pay for performance in this study are primary care facilities.
Erickson 2016	In this study the participants are physicians in haemodialysis facility and their patients, but only patients are described and there is no more information about the physicians.
Erickson 2017	The intervention in this study is for inpatients.
Erus 2017	Not designed as a CBA study, no control group
Feng 2015	Not a CBA study design, but rather a before‐after comparative study without control group
Gallagher 2015	The provider is institution.
Giguere 2015	The intervention of this study is not related to payment methods.
Greene 2013	The interventions are for both general practitioners and general practices.
Hamilton 2016	Not a CBA study design, but rather a before‐after comparative study without control group
Han 2015	This study does not have at least 3 time points before and 3 after the intervention. An interrupted time‐series analysis allows separate analysis of immediate effects and monthly trends following policy implementation, but it is shown through 3 periods.
Hickey 2015	Not a CBA study design; only 1 site
Hysong 2017	The participants of the study are not ambulatory care professionals.
Jones 2015	Not a CBA study design; no control group
Kiran 2015	Not a CBA study design. It does not have a clearly defined point in time, but just describes the change trend of different physicians payment methods.
Kliner 2015	Not a CBA study design. The intervention was only performed in a regional hospital, which made it difficult to attribute any observed differences to the intervention rather than to other site‐specific variables.
Lagarde 2016	The participants in this study are not in outpatient care facilities.
Lee 2010	Participants of this study were patients. Although the physicians could enrol individual patients in the programme and receive regular reimbursement, there is no description of physicians, and not all the physicians come from outpatient facilities.
Lee 2015	The participants of this study are patients.
Lezzi 2014	Not an RCT, CBA, or ITS study design; a panel count data model is used
Lix 2016	This study is not designed as a CBA, but rather a retrospective case‐control study.
Maini 2014	The participants of this study are facilities, and the intervention objects are patients.
Merilind 2015	This study is not designed as an ITS. It compared childhood immunisation coverage rates of all Estonian family physicians in 2 groups, joined and not joined to the quality system, during the observation period of 2006 to 2012. Also, the family physicians had joined the quality system and were not assigned by investigators in 2006.
Michel 2015	Cross‐sectional study
Mullen 2009	Provider is not clear.
Murray 1992	Cross‐sectional study
Odesjo 2015	The participants of this study are practices.
Olivier 2015	Not a CBA study design; no control group
Petersen 2016	The participants in this study are in‐hospital, and the incentives are for both physicians and facility.
Ritchie 1992	Not an ITS study; it only measured 7 quarters after intervention
Robertson 2017	This study used quality measure, plan‐do‐study‐act, root‐cause analyse, lean six sigma.
Roski 2003	The participants of the study are clinics.
Rudasingwa 2017	The participants of this study are healthcare facilities.
Shelley 2012	Not about payment methods
Shen 2003	The provider is not clear.
Shen 2017a	The participants of the study are health centres.
Shen 2017b	The participants of the study are not ambulatory care professionals.
Sicsic 2015	Not a CBA study; only a before‐and‐after study
Simonsen 2017	The intervention in this study is not related to payment methods.
Simpson 2011	The participants of this study were patients. Physicians are only mentioned in the background (intervention can increase a doctor's income).
Stearns 1992	Not a CBA study; only a before‐and‐after study
Sun 2016	The participants of this study are healthcare facilities.
To 2015	Cross‐sectional study
van Dijk 2014	Not a CBA study design, just a simple before‐after comparative study
van Dijk 2015	Not a CBA study; no control group
Vats 2014	The participants of this study are primary care practices.
Wei 2015	The intervention in this study was just an assumption.
White 2006	The participant is not health care professionals in ambulatory care facilities.