Randomized controlled trials that cover at least the most common types of chronic wounds (arterial, venous, diabetic or pressure sore) are recommended as the best method for gathering evidence. Despite the heterogeneous etiology of chronic wounds, the results should also be transferable to other wound types. The test intervention does not usually consist of the sPW alone, but of a combined wound treatment that follows a treatment plan that is as clearly defined as possible. In the comparison group, all wound treatment options (besides the sPW) must also be available and used according to a similar predefined treatment plan. Depending on the intended purpose and treatment goal, complete wound closure should, if possible, be recorded as the cardinal - although not always as the primary - endpoint. In justified cases, e.g. in the case of intermediate use as part of phase-appropriate wound therapy for chronic wounds, a significant reduction in the wound area can also be considered for benefit assessment. Quality of life (e.g. pain) can also justify a benefit and can therefore be recorded as a primary outcome parameter in clinical trials. The duration of the clinical trial should be adapted to the central endpoints, the medical or nursing goal of wound care and the intended purpose of the sPW. A benefit does not always arise from microbiological, physiological, laboratory or histological parameters or imaging findings.