Table 1. Eligibility criteria.

	Inclusion Criteria	Exclusion Criteria
Population	Studies conducted in England and/or Wales from 2007, when the Mental Capacity Act (2005) was implemented. Participants aged 16 years and above (the age at which the MCA applies), with communication and/or capacity difficulties (e.g. associated with autism; stroke; mental health; dementia; acquired brain injury; and intellectual disabilities);	Research studies governed by The Medicines for Human Use (Clinical Trials) Regulations 2004. Research using tissue samples. Secondary data.
Intervention	• Invoking the provisions for research under the MCA (2005).
Outcomes	Demographic data Recruitment procedures Accommodations supporting research participation.
Study designs	Any; quantitative, qualitative, mixed study design
Publication types	*Primary empirical studies from peer-reviewed literature
Publication year	2007 to 2019
Language	English language

Notes:

*The year the study was conducted indicated when participants were recruited.

When the date was not provided, clarification was sought by sending an email to the corresponding author and searching the publicly available Health Research Authority (HRA) database. Finally, where this could not be established, we back-tracked three years from publication data on the basis that the majority of studies are published within 30 months post the live period of a study (i.e., from 2010) [48].