Who is a credible source of preventive advice? An experimental vignette study of general public attitudes towards role expansion in health and social care.

Objectives: To investigate the general public's source credibility attitudes towards health and social care professionals when giving advice associated with their 'traditional role' versus an 'expanded health behaviour change' role, to facilitate the implementation of the health behaviour change agenda.

Design: A 3x3 experimental between-subjects vignette questionnaire study with nine scenarios in which a general practitioner (GP), health visitor, or firefighter offered advice on either stopping smoking, preventing cot death, or fire safety. Combinations were either congruent with a traditional role (e.g., health visitor and cot death) or an expanded role (e.g., firefighter and stopping smoking).

Methods: Adults were recruited from metropolitan locations in northern England. Participants were randomized to one scenario and complete a validated 18-item source credibility questionnaire. Factor analysis explored source credibility components; ratings for traditional and expanded role scenarios were compared using Mann-Whitney tests.

Results: 369 participants completed the questionnaire (49.3% women, 64% White British, age range: 16-83). Factor analysis confirmed three source credibility dimensions: competence, caring, and trustworthiness. Ratings were generally high across professions and scenarios; participants rated professionals as significantly more 'competent' where scenarios related to their traditional roles than expanded roles (U  9778.5, p  <.001) but equally as caring (U = 14467.5, p< .485) and trustworthy (U  14250.5, p  .348).

Conclusions: GPs, health visitors, and firefighters were all perceived as credible sources of health behaviour change advice, but may be viewed as 'less competent' sources of messages associated with an expanded job role. Effective professional training and public engagement regarding the role expansion agenda are needed to support policy implementation. Statement of Contribution What is already known on this subject? Source credibility surrounds people's perceptions of the source of advice and includes competence, caring, and trustworthiness dimensions. This may have an important influence on people's attitudes and behaviour, especially when messages are complex or emotive. A wide range of public sector workers is now expected to routinely offer preventive health and safety advice, as part of role expansion. What does this study add? This experimental survey study compared source credibility perceptions of GPs, health visitors, and firefighters giving advice on topics associated with a traditional or expanded role. Professionals were perceived as less 'competent' when giving advice on 'expanded role' topics, such as a firefighter discussing smoking, with a small reduction in source credibility. This highlights that source credibility may be specific to professional identities. Policymakers may need to explore this further as part of implementing role expansion for prevention and self-management in health and social care.