Knowledge user involvement is still uncommon in published rapid reviews-a meta-research cross-sectional study. - Nussbaumer-Streit B; Ledinger D; Kien C; Klerings I; Persad E; Chapman A; Nowak C; Gadinger A; Affengruber L; Smith M; Gartlehner G; Griebler U (Research synthesis methods, 2025)