Table 2 Description of the thematic categories and sub-themes that emerged from the literature

General sub-themes

1.1. What is an LESs: Understanding a living synthesis as a summary of all existing research that is up-to-date at any defined point in time

1.2. What is an update: Understanding what constitutes an ‘update’ in the context of an LES

1.3. Labeling ‘living’: What do we understand by the label ‘living’

2.1. Assessment of the need of an LES: Methods to predict whether:

- new literature might change the findings

- the likelihoods of the existing findings to change

- the value that new information would provide in reducing uncertainty

- or how the context and issue might change the applicability of the findings

2.2. Team management: Methods to facilitate team management while producing an LES

2.3. Production: Methods to facilitate the production (searching, selecting studies, extracting data, assessing risk-of-bias and synthesizing data) of an LES

3.1. Types of decision: Alternatives for an evidence producer when starting a new evidence synthesis:

- starting a new synthesis

-updating a synthesis

-making A synthesis living)

3.2. Other elements to consider other elements to be considered when making a decision of when an LES needs to be conducted (e.g., workload, context, etc.)

4.1. Processed involved: Parts of an evidence synthesis that could be updated, including search methods, data synthesis and publication

4.2. Frequency: deciding how frequent an LES needs to be updated, with what support researchers count on making this decision, and the need for researchers to commit to reliable schedules for updates

5.1. Platforms: different options that could be used to make available the findings:

-website

- scientific journal

-interactive platforms

5.2. Structured format: different adaptations to the format of an LES that can be used to streamline dissemination processes

5.3. LES users: types of decision-makers and evidence intermediaries that can use the findings of LESs, and the need for evidence producers to tailor the presentation depending on the type of user

5.4. Speeding-up: strategies that can be used to reduce the time from which findings are available and they are used by decision-makers and evidence intermediaries, including pre-prints, small-indexed publications notifying updates

6.1.Other elements to consider: other elements to be considered when making a decision of when an LES can stop being updated, including the engagement of the synthesis team, and the planned obsolescence of an LES

Sub-themes associated with ‘triggers’

3.3. Triggers to produce an LES:

- Demand-side triggers: relevancy of the topic for decision-making (i.e., priority issue)

- Supply-side triggers: likelihood of the existing evidence to be changed, and the probability that new evidence might change the findings

4.3. Triggers to update an LES:

- Demand-side triggers: changes in the priority of an issue for decision-making

- Supply-side triggers: changes in the likelihood of the existing evidence to be changed, and the probability that new emerging evidence might change the findings

6.2. Triggers to discontinue an LES:

- Demand-side triggers: the issue is no longer a priority, or the research question could be re-framed

- Supply-side triggers: no new evidence is expected to be available or the findings of the existing evidence are unlikely to change

Citations

[5, 17, 18, 20, 21, 23, 29, 32, 32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119]

[5, 12, 13, 19, 22,23,24,25,26,27,28,29, 31, 37, 38, 40, 43, 44, 46, 47, 50,51,52,53,54, 56, 59, 65, 67,68,69,70,71, 77, 80, 88, 92, 93, 95, 96, 98, 99, 103, 108, 110, 120, 120,121,122,123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144,145,146,147,148,149,150,151,152,153,154,155,156,157,158,159,160,161,162,163,164,165,166,167,168,169,170,171,172,173,174,175,176,177,178,179,180,181,182]

[5, 16, 21, 30, 33, 37, 38, 42, 44,45,46,47,48,49, 52,53,54,55,56, 58, 60, 65, 66, 71, 72, 76, 77, 87, 88, 90, 91, 93, 96,97,98,99, 101, 104, 110, 113, 114, 116, 117, 123, 131, 133,134,135,136, 140, 141, 148,149,150, 165, 173, 183,184,185,186,187,188,189,190,191,192,193,194,195,196]

[15,16,17,18, 28, 30, 32, 38, 39, 42, 45, 47, 49, 50, 54, 56,57,58, 62, 66, 69, 71, 73, 76, 86, 88, 92, 93, 96,97,98,99, 116, 119, 120, 120, 122, 124, 126, 127, 129,130,131, 134, 136, 142, 144, 148, 150, 156, 157, 160, 173, 176, 184, 190,191,192,193,194, 196,197,198,199,200,201,202,203,204,205,206,207,208,209]

[5, 29, 34, 37, 39,40,41, 46, 51,52,53,54, 56, 61, 62, 65,66,67, 70, 72, 73, 78, 80, 83, 87, 92, 93, 95, 96, 98, 99, 103, 104, 106, 108,109,110, 113, 119, 123,124,125, 133, 135, 141, 147,148,149,150, 163, 169, 171, 177, 195, 196, 203, 206,207,208,209,210,211,212,213,214,215,216,217,218,219,220]

[16, 30, 37, 37, 38, 50, 55, 56, 66, 70, 88, 91,92,93, 101, 116, 134, 136, 148, 151, 155, 185, 221]