Qualitative evidence synthesis (QES) is a broad term, popularised within the Cochrane Collaboration, for the group of methods used to undertake systematic reviews of qualitative research evidence.
Authors should always consult current methods guidance at methods.cochrane.org/qi.
Flemming, K., Booth, A., Garside, R., Tunçalp, Ö., & Noyes, J. (2019). Qualitative evidence synthesis for complex interventions and guideline development: clarification of the purpose, designs and relevant methods. BMJ global health, 4(Suppl 1), e000882. Link
Cochrane training: Chapter 21 Qualitative Evidence. Link
Cooke, A., Smith, D., & Booth, A. (2012). Beyond PICO: the SPIDER tool for qualitative evidence synthesis. Qualitative health research, 22(10), 1435–1443. Full Text
Odendaal, W. A., Anstey Watkins, J., Leon, N., Goudge, J., Griffiths, F., Tomlinson, M., & Daniels, K. (2020). Health workers' perceptions and experiences of using mHealth technologies to deliver primary healthcare services: a qualitative evidence synthesis. The Cochrane database of systematic reviews, 3(3), CD011942. Full Text