[What is a public health intervention? Results of a Delphi process in German-speaking countries]

Internationally, a variety of definitions for public health interventions (PHI) exist. In the German-speaking countries, however, a definition is still outstanding. Therefore, the aim of this study was to derive consensus criteria for the definition of PHI from the expert perspective of science and practice.

A Delphi survey with two online rounds was conducted from December 2022 to February 2023. Six criteria were formulated by a working group and posed for consensus: 1) the intention of the intervention, 2) potential conflicts of interest of the initiators of the intervention, 3) primary vs. secondary/tertiary prevention, 4) costs, 5) targeting, and 6) the reach of the intervention. In both Delphi rounds, experts from academia and practice were recruited through relevant networks and associations throughout the German-speaking world. The judgments were asked about standardized rating scales with the possibility of open justification.

In the first Delphi round, n = 52 and in the second round n = 43 experts from research, care and administration/management in health care participated. Consensus was reached on four of the six criteria after the second Delphi round: the intention of the intervention, possible conflicts of interest of the initiators of the intervention, primary vs. secondary/tertiary prevention, and the scope of the intervention. From the perspective of the experts interviewed, these are the criteria that distinguish PHI.

Based on the consensus criteria, PHI can be defined more concretely. Thus, the results contribute to a better inter- and transdisciplinary understanding. Ideally, the criteria will make it easier to assign interventions to the public health sector in the future, even if a precise examination will be necessary in individual cases, among other things because the experts disagreed on the criteria of costs and how to address the target group.