Commentary on Kraiss et al.: Read the label - improving the applicability of systematic reviews by coding and analysis of intervention elements

While controlled trials are crucial for establishing an intervention's effectiveness, knowing what was assessed and what it was compared to is often mysterious. Trustworthy replication and application both require a sufficiently clear ‘recipe’ for the experimental and control interventions that other researchers and clinicians could use them. This problem of description is further complicated our fuzzy language: phrases such as ‘brief physician advice’, ‘nurse counselling’, ‘self-help’ and ‘usual care’ can each give the illusion of a singular, well-delineated intervention. The study by Kraiss et al. [1] demonstrates just how illusory this can be for both intervention and the usual care. More importantly, they demonstrate how the elements of intervention and usual care might be unravelled. Such methods are vital for both research progress and for real-world application.