Fig. 3

Process model for the assessment of transferability (PIET-T process model). Figure 3 shows the process of the assessment of transferability of health interventions derived from the analysis and includes descriptive themes and criteria of the population (P), intervention (I), environment (E), and transfer (T). The PIET-T process model is intended to accompany the steps for determining transferability: The analysis of the health problem is based on the (baseline) characteristics of the population in the target context in order to search for an effective intervention. Because transferability is dependent on the conditions in the primary and target context, a comparison of both contexts should be attempted. This requires both information from the primary context and from the target context. The themes and criteria, which are mapped around the process, are intended to help determine which information is relevant for the target context and for a comparison with existing information on the primary context. By assessing the criteria, facilitators and barriers can also be identified. However, transferability cannot be measured in this phase, but can only be anticipated using existing information. An identification of transferable (core) elements of the intervention and the need for adaptation may be relevant, depending on the complexity and character of the intervention and its conception, the population characteristics, and the environmental conditions. The steps of implementation and evaluation are well known steps of process models. Finally, transferability can only be assessed after evaluation by measuring the effectiveness of the intervention. The evaluation may lead to sustaining or advancing of the intervention, to changing of its (core) elements or modifying of specific aspects, or to stopping of the intervention