RESUMO
Efficacy and effectiveness of psychotherapy are well studied, but we know little about optimal ways of delivering therapy. Evidence of how best to deliver psychotherapy is scarce and difficult to scope because reports of how interventions are delivered lack a common terminology. We therefore conducted a Delphi study on what dimensions of therapy delivery are important to report and examine. The study was conducted between October 2016 and July 2017. Twenty therapy experts rated and commented on various dimensions of therapy delivery (e.g., duration, spacing, or format of session). Experts were asked (a) how relevant these were for reporting of therapy studies, (b) how much they agreed with the guidelines for describing them, (c) how important these were to investigate in future studies, and (d) whether they agreed with the name of the dimension. Experts were asked to suggest other dimensions of therapy delivery they considered relevant and propose revisions of the initial guidelines. The panel agreed on names and guidelines for the description of 13 dimensions of therapy delivery. These were deemed relevant or highly relevant to report and research in future psychotherapy studies. We propose structured guidelines for reporting the delivery of psychotherapy.