Table 2.

Characteristics of included tools

Name (abbreviation)a [References]	Type and source						Scalability component targeted by toolsb											Number of items	Pitfall predictionsc
	Type	Year of issue or publication	Source of funding	Language	Type of stakeholder	Open-access source	C1	C2	C3	C4	C5	C6	C7	C8	C9	C10	C11
Innovation Scalability Self-administered Questionnaire (ISSaQ) [2, 3]	Checklist	2017	Governmental organization	English, French	Researcher	Peer-reviewed journal		✓		✓	✓	✓	✓	✓	✓	✓	✓	16	${\text{P}}_{3,8}$
AnalySe de la Transférabilité et accompagnement à l’Adaptation des Interventions en pRomotion de la santE (ASTAIRE) [53, 54]		2013	Governmental organization	English, French	Researcher	Peer-reviewed journal	✓	✓		✓	✓	✓	✓	✓	✓	✓		23	${\text{P}}_{2,3,7,8}$
WHO/ExpendNet [123, 124]		2011	Governmental and nongovernmental organizations	English	Not found	Organizational website	✓	✓	✓	✓	✓	✓			✓	✓		23	${\text{P}}_{1,3,4,7,8}$
Scalability Checklist [127–129]		2016	Nongovernmental organization	English	Not found	Organizational website	✓			✓	✓	✓	✓	✓	✓	✓		7	${\text{P}}_{3,8}$
Baker et al. [47]	Criteria	2011	Governmental organization	English	Not found	ResearchGate			✓					✓	✓	✓		16	${\text{P}}_{1,2,6,7,8}$
Bennett et al. [48]		2017	Governmental organization	English	Not found	Peer-reviewed journal			✓		✓	✓	✓	✓		✓	✓	8	${\text{P}}_{3,8}$
Burchett et al. [50]		2011	Not found	English	Researcher	ResearchGate			✓		✓	✓	✓	✓	✓		✓	17	${\text{P}}_{3,5,8}$
Burchett et al. [51]		2012	Governmental organization	English	Clinician, policy-maker, researcher	Not found	✓		✓		✓	✓	✓	✓	✓		✓	15	${\text{P}}_{3,6,7,8}$
Cambon et al. [52]		2012	Governmental organization	English	Not found	Peer-reviewed journal	✓	✓	✓	✓		✓	✓	✓	✓	✓		32	${\text{P}}_{1,3,6,7,8}$
Process model for the assessment of transferability (PIET-T) [55]		2018	Governmental organization	English	Not found	Peer-reviewed journal	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	✓	14	${\text{P}}_{2,8}$
Spicer et al. [56]		2014	Nongovernmental organization	English	Policy-maker, researcher, civil society organizations	Peer-reviewed journal	✓		✓	✓	✓	✓	✓	✓	✓			22	${\text{P}}_{3,8}$
Wang et al. [58]		2005	Not found	English	Not found	Not found	✓			✓			✓	✓	✓	✓		12	${\text{P}}_{6,8}$
Milat et al. [20, 21, 120]		2012	Governmental organization	English	Policy-maker, researcher	Peer-reviewed journal, ResearchGate, organizational website				✓	✓	✓	✓	✓	✓	✓	✓	21	${\text{P}}_{3,5,8}$
CORRECT attributesd [6, 121, 122]		2010	Governmental organization	English, French, Spanish	Not found	Organizational website	✓		✓		✓	✓	✓		✓	✓		17	${\text{P}}_{3,6,8}$
Bhattacharyya et al. [49]	Scale	2017	Governmental and nongovernmental organizations	English	Policy-maker	Peer-reviewed journal			✓	✓	✓		✓		✓			8	${\text{P}}_{2,3,8}$
Scalability assessment framework [57]		2018	Nongovernmental organization	English	Not found	Not found	✓	✓	✓	✓		✓	✓		✓	✓	✓	16	${\text{P}}_{3,7,8}$
Intervention Scalability Assessment Tool (ISAT) [22]		2019	Governmental organization	English	Clinician, policy-maker, researcher	Organizational website	✓		✓	✓	✓	✓	✓	✓	✓	✓	✓	19	${\text{P}}_{3,8}$
Readiness to Spread Assessment Scoring Sheet [125]		2013	Not found	English	Not found	Organizational website			✓		✓		✓	✓		✓	✓	4	${\text{P}}_5$
Readiness to Receive Assessment Scoring Sheet [126]		2013	Not found	English	Not found	Organizational website				✓					✓	✓		4	${\text{P}}_8$
Applicability and Transferability of Evidence Tool (A&T Tool) [118, 119]		2007	Governmental organization	English, French	Not found	Organizational website	✓			✓		✓	✓	✓	✓			21	${\text{P}}_{3,7,8}$
Scalability Assessment and Planning (SAP) Toolkit [130]		2018	Not found	English	Researcher	Organizational website					✓		✓			✓	✓	5	Not found

^aWe did not find names for 10 of the tools, in which case we indicated names of authors or organizations

^bScalability components targeted: (${\text{C}}_1$) health problem addressed by the innovation; (${\text{C}}_2$) development process of the innovation; (${\text{C}}_3$) innovation characteristics; (${\text{C}}_4$) strategic, political or environmental context of the innovation; (${\text{C}}_5$) evidence available for effectiveness of the innovation; (${\text{C}}_6$) innovation costs and quantifiable benefits; (${\text{C}}_7$) potential for implementation fidelity and adaptation of the innovation; (${\text{C}}_8$) potential reach and acceptability to the target population; (${\text{C}}_9$) delivery setting and workforce; ${\text{C}}_{10}$) implementation infrastructure required for scale-up; and (${\text{C}}_{11}$) sustainability (i.e. longer-term outcomes of the scale-up)

^cPitfalls of scale-up relate to: (${\text{P}}_1$) sex and gender considerations; (${\text{P}}_2$) patient and public involvement; (${\text{P}}_3$) the difficulty of cost-effectiveness estimates; (${\text{P}}_4$) the production of health inequities; (${\text{P}}_5$) scaled-up harm; (${\text{P}}_6$) ethics (e.g. informed consent at scale); (${\text{P}}_7$) top-down approaches (i.e. the needs, preferences and culture of beneficiaries of the innovation may be forgotten when scale-up is directed from above); and (${\text{P}}_8$) context (e.g. difficulty in adapting the innovation to certain contexts)

^dCORRECT attributes: C—credible in that they are based on sound evidence or advocated by respected persons or institutions; O—observable to ensure that potential users can see the results in practice; R—relevant for addressing persistent or sharply felt problems; R—relative advantage over existing practices so that potential users are convinced the costs of implementation are warranted by the benefits; E—easy to install and understand rather than complex and complicated; C—compatible with the potential users’ established values, norms and facilities; fit well into the practices of the national programme; and T—testable so that potential users can see the innovation on a small scale prior to large-scale adoption

✓ is a checkmark for the item