Systematic reviews of empirical bioethics

Background: Publications and discussions of survey research in empirical bioethics have steadily increased over the past two decades. However, findings often differ among studies with similar research questions. As a consequence, ethical reasoning that considers only parts of the existing literature and does not apply systematic reviews tends to be biased. To date, we lack a systematic review (SR) methodology that takes into account the specific conceptual and practical challenges of empirical bioethics. Methods: The steps of systematically reviewing empirical findings in bioethics are presented and critically discussed. In particular, (a) the limitations of traditional SR methodologies in the field of empirical bioethics are critically discussed, and (b) conceptual and practical recommendations for SRs in empirical bioethics that are (c) based on the authors' review experiences in healthcare ethics are presented. Results: A 7-step approach for SRs of empirical bioethics is proposed: (1) careful definition of review question; (2) selection of relevant databases; (3) application of ancillary search strategies; (4) development of search algorithms; (5) relevance assessment of the retrieved references; (6) quality assessment of included studies; and (7) data analysis and presentation. Conceptual and practical challenges arise because of various peculiarities in reviewing empirical bioethics literature and can lead to biased results if they are not taken into account. Conclusions: If suitably adapted to the peculiarities of the field, SRs of empirical bioethics provide transparent information for ethical reasoning and decision-making that is less biased than single studies.