[Introduction to qualitative evidence synthesis - Variants and application]

Qualitative evidence syntheses (QES) are still uncommon in German rehabilitation research, although robust syntheses of qualitative evidence may lead to more strongly scientifically based decisions in health care. This article introduces the topic of qualitative evidence synthesis by describing three different synthesis methods - thematic synthesis, meta-ethnography, and grounded theory synthesis - and illustrating them with examples from rehabilitation research. This is followed by guidance on selecting the appropriate QES-method and reflections on the challenges of QES that are associated with the literature search and quality assessment of the studies to be included in the synthesis. Likewise considerations on quality criteria and their application are taken into account. GRADE-CERQual provides guidance for assessing confidence of findings from QES. Finally the value of QES for rehabilitation research is discussed.