Table 1 List of unique element categories and synonyms. For full reference to the included evidence syntheses, see Additional file 4

0

No reported method or element

This category is presented in eight reviews (Badakhshan et al., 2018; Bryant et al., 2014; Garcia et al., 2015; Manafo et al., 2018; McGregor et al., 2014; Pii et al., 2019; Reveiz et al., 2013; Rylance et al., 2010). This category includes COHRED, descriptive study, qualitative study, road map 1, national call, not mentioned, CHNRI, pilot test, and pretest

1

Interviews

This category is presented in seven reviews (Badakhshan et al., 2018; Erntoft, 2011; Manafo et al., 2018; McGregor et al., 2014; Pii et al., 2019; Tong et al., 2015; Tong et al., 2017). This category includes interviews, in-depth interviews, semi-structured interviews, telephone interviews, key informant interviews, group interviews, interview/focus groups, pilot interviews, individual interviews, and semi-structured telephone interviews

2

Surveys

This category is presented in 10 reviews (Badakhshan et al., 2018; Booth et al., 2018; Bryant et al., 2014; Erntoft, 2011; Garcia et al., 2015; Manafo et al., 2018; McGregor et al., 2014; Pii et al., 2019; Tong et al., 2015; Tong et al., 2017). This category includes surveys, online surveys, questionnaires, web questionnaires, postal surveys, telephone surveys, the value-weighting survey method, classic weighting questionnaires, surveys of decision-making groups, surveys of research groups, surveys of funding organisations, stakeholder surveys, the listening approach, qualitative questionnaires, and interim surveys

3

Experts

This category is presented in seven reviews (Badakhshan et al., 2018; Bryant et al., 2014; Garcia et al., 2015; McGregor et al., 2014; Pii et al., 2019; Rylance et al., 2010; Tong et al., 2015). This category includes expert panels, expert forums, expert committees, expert opinions, advisory groups, expert reviews, expert research commentary, expert meetings, expert subgroups, stakeholder meetings, morphological options, advisory boards, and task forces (ENHR)

4

Workshops

This category is presented in eight reviews (Badakhshan et al., 2018; Bryant et al., 2014; Manafo et al., 2018; McGregor et al., 2014; Pii et al., 2019; Reveiz et al., 2013; Rylance et al., 2010; Tong et al., 2017). This category includes workshops, conferences/workshops, workshop consultations, working groups, working group consultations, breakout sessions, group exercises, committee meetings by conference call, and consultations

5

Focus groups

This category is presented in 11 reviews (Badakhshan et al., 2018; Booth et al., 2018; Bryant et al., 2014; Garcia et al., 2015; Manafo et al., 2018; McGregor et al., 2014; Pii et al., 2019; Reveiz et al., 2013; Rylance et al., 2010; Tong et al., 2015; Tong et al., 2017). This category includes focus groups, focus group discussions, nominal focus groups, webinars with work groups, brainstorming, nominal group techniques, case studies/community consultation models, and online forums

6

Delphi approaches

This category is presented in 10 reviews (Badakhshan et al., 2018; Booth et al., 2018; Bryant et al., 2014; Garcia et al., 2015; Manafo et al., 2018; McGregor et al., 2014; Pii et al., 2019; Reveiz et al., 2013; Tong et al., 2015; Tong et al., 2017). This category includes Delphi, the Delphi method, the modified Delphi technique, the James Lind Alliance research priority setting, and the Hanlon method

7

Stakeholder involvement

This category is presented in eight reviews (Badakhshan et al., 2018; Bryant et al., 2014; Garcia et al., 2015; Manafo et al., 2018; McGregor et al., 2014; Pii et al., 2019; Reveiz et al., 2013; Tong et al., 2017). This category includes panels with stakeholders, patient engagement panels, stakeholders, dialogue models, research needs assessment, stakeholder involvement, participation action research, deep inclusion, consumer reference group discussions, public consultations, engagement of key organisations, consultation re priorities, stakeholder roundtables, patient panels, community-based organisation partners, community advisory groups, community meetings, and feedback

8

Document analyses

This category is presented in five reviews (Bryant et al., 2014; Erntoft, 2011; Garcia et al., 2015; McGregor et al., 2014; Tong et al., 2017). This category includes environmental scans of policy issues, document analyses, analyses of a country’s situation on health, comparisons with policy, white papers, reviews of guidelines, and review/environmental scans

9

Observations

This category is presented in two reviews (Badakhshan et al., 2018; Erntoft, 2011). This category includes observations, participant observations of deliberations, observations of committee meetings, observations of deliberations

10

Consensus

This category is presented in seven reviews (Badakhshan et al., 2018; Bryant et al., 2014; Garcia et al., 2015; McGregor et al., 2014; Reveiz et al., 2013; Tong et al., 2015; Tong et al., 2017). This category includes consensus, group consensus, voting, weighting methods, rapid appraisal, roundtable discussions, go zones, public sessions, consensus metrics approaches, two meeting groups, consensus ranking, thematic analyses, workshops with the nominal group technique, interim voting, and pooling

11

Reviews of literature

This category is presented in nine reviews (Badakhshan et al., 2018; Booth et al., 2018; Bryant et al., 2014; Manafo et al., 2018; McGregor et al., 2014; Pii et al., 2019; Rylance et al., 2010; Tong et al., 2015; Tong et al., 2017). This category includes literature reviews, the James Lind Alliance research priority setting, systematic reviews, and evidence mapping

12

Ranking methods

This category is presented in eight reviews (Badakhshan et al., 2018; Garcia et al., 2015; Manafo et al., 2018; McGregor et al., 2014; Pii et al., 2019; Reveiz et al., 2013; Rylance et al., 2010; Tong et al., 2015; Tong et al., 2017). This category includes the Likert scale, weighting with the Likert scale, numerical scales, metrics, key informant ranking exercises, community consultation models, ranking, community partnered participatory research models, and discrete choice experiments

13

Conferences

This category is presented in five reviews (Garcia et al., 2015; Manafo et al., 2018; McGregor et al., 2014; Tong et al., 2015; Tong et al., 2017). This category includes meetings, seminars, retreats, teleconferences, conference calls, strategic planning meetings, multistage process meetings, and road map conferences