Table 4 Types of intervention identified in the literature and programme theories developed

Single-session interventions (n = 13) [73, 76, 86, 88, 89, 91, 95, 111, 137, 141, 143, 162, 174]

Single, one-off lectures or workshops to try to change participant behaviour. This can employ awareness-raising strategies such as education about UB, or can be combined with role-playing and other activities intended to enhance the ability to speak up and challenge UB in the moment

CMOC 1. If an intervention relies solely on single sessions (C), then while they may raise awareness and knowledge of skills to tackle UB in an organisation in the moment (O1), any planned behaviour change may not be sustained (O2), because they are intended as a one-time delivery of information or training and may be forgotten (M)

CMOC 2. If an intervention relies solely on single sessions (C), then behaviour and sustained culture change may not happen (O), because it relies on individual behaviour change without any parallel organisation-wide approach (M)

Multi-session interventions (n = 11) [82, 94, 100, 106, 125, 129, 144, 154, 156, 172, 177]

These are similar to single-session interventions but rely on use of multiple workshops or lecture-type sessions over time. Most still draw on education and role-playing type activities

CMOC 3. If an organisation seeks to implement a multi-session intervention, then, compared to single-session interventions (C), a greater transference of intervention content will occur (O), because it is possible to include more material, and learning is repeated and reinforced, facilitating greater knowledge retention (M)

Combined sessions with other activity interventions (n = 6) [83, 92, 93, 108, 116, 164];

These typically draw on single or multiple sessions as above, but also enhance this with non-session-based activities such as implementing an organisation-wide code of conduct

CMOC 4. If an organisation implements sessions combined with other strategies (e.g. a code of conduct) (C), then this may increase the spread of knowledge about how to address UB (O), resulting in both systemic change and individual knowledge gain/attitude changes through training or education (M)

Professional accountability interventions (n = 8) [74, 78, 101, 122, 126, 160, 165, 178];

These are more complex than those outlined above, relying on a reporting and escalation system. Examples include Ethos and Vanderbilt interventions. These interventions typically combined a reporting system with, in the case of Ethos [74, 126], training to enhance speaking up and role-modelling by leadership or, in the case of Vanderbilt interventions, incorporated championing (i.e. encouraging individuals to role-model and espouse the benefits of the intervention)

CMOC 5. If reporting and escalation systems and education about how to use them are implemented to address UB (C), then a clear message of no tolerance is sent to employees (O), because a new and structured route for speaking up and reporting UB is created (M)

Structured culture change interventions (n = 4) [120, 127, 132, 169]

These include CREW which offers a flexible package enabling organisations to respond to UB as needed, building upon (1) ongoing action planning to assess which strategies to implement and (2) surveys to understand prevalence and spread of UB. Strategies included training on assertiveness, communication and conflict resolution, as well as management training for leaders and other strategies that help build rapport between staff

CMOC 6. If organisations have access to financial and material resources that allow them to address UB in a setting-specific manner with a structured culture change intervention (C), then they will be better able to tailor their response to local UB as it occurs (O), allowing for contributors to be more directly addressed over time (M)