Poster can be found in location 130.

Professional nursing is social action in complex systems. The effect and effectiveness of nursing action can therefore not be explained by considering isolated technical and functional procedures. Rather, they emerge as a process, both through intentional action and through relational interaction. From a methodological point of view, this leads to a conundrum: while there is a pressing need to demonstrate the effectiveness of person-centred interventions, traditional approaches to effectiveness research repeatedly face limitations. The aim of the talk is to elucidate the role of the nurse as a person in intervention research from the perspective of person-centred care theory and to derive methodological implications for intervention research. Generative mechanisms and cause-effect relationships theorised in selected nursing programme theories from various fields, including dementia care, palliative care, and family counselling, serve as an empirical basis. For the ‘production’ of effective nursing, person-centredness, as reflected in the nurse’s attitude, is the prerequisite. It forms the basis for a hermeneutic process in which different forms of knowledge are integrated and lead to actions tailored to the individual situation.  Traditional approaches to knowledge production need to be reconsidered with regard to the role of the nurse in the effectiveness of nursing action, not least through the approach of person-centred theory. Concepts such as determinism, replicability, or standardisation conflict with this view, in which the nurse is considered a central factor, rather than a potential source of bias or confounding. Intervention research may benefit from exploring alternative methodologies such as theory-based evaluations, which acknowledge the embeddedness and social nature of interventions. This could be one way of overcoming the apparent mismatch between person-centred practice and traditional designs of effectiveness research at the methodological level.