Introduction Patient and public involvement (PPI) is critical for scaling shared decision making. We aim to provide an overview on how patients and the public are involved in scaling initiatives in health and social services.

Methods In a scoping review, we included any scaling initiative in health and social services that used PPI strategies and reported any outcome. We searched databases from inception to September 2020, and grey literature. Paired reviewers selected and extracted eligible records. We performed a narrative synthesis. We used the Preferred Reporting Items for Scoping Reviews and the Guidance for Reporting Involvement of Patients and the Public.

Results We included 77 unique reports that reported 87 scaling initiatives. Most initiatives that targeted a country occurred in higher-income countries (n = 29). Most scaling initiatives involved patients and the public throughout all phases of the scaling (n = 39). Most PPI was at the level of collaboration (n = 36); most frequently reported ethical lenses for PPI were consequentialist-utilitarian (aiming to increase effectiveness) (n = 68).

Discussion Patients and the public are increasingly involved in all phases of scaling. Although collaboration was frequently reported, the practice of co-production does not seem to be well- established yet in the context of scaling. Also, there is a need for more available evidence about how key scaling participants in low- and middle-income countries perceive and communicate about PPI in scaling using their own local concepts, terminology, and knowledge. Finally, a combination of ethical lenses is required in approaching PPI, fostering an understanding of PPI not only as an instrument for increasing effectiveness but also as a duty, a right, and a guiding principle.

Conclusions PPI in scaling is increasing in health and social care services but co-production is still a challenge. Co-construction requires extra resources that should be anticipated for scaling.