Summary of effectiveness of policies and non-policy interventions on outcomes, by the level of intrusiveness*†
| Level of intrusiveness of the interventions | Ever-use and/or initiation | Susceptibility | Beliefs and perceptions on harms, risks and social norms | Attitudes and behaviours | Knowledge | Reactions to or perceptions of the intervention’s effectiveness |
| Eliminate choice | Effective (four studies) | Effective (one study only) | Effective (one study only) | Effective (one study only) | ||
| Restrict choice | Effective (one study only) | |||||
| Guide choices through disincentives | Not effective (one study only) | |||||
| Guide choices through incentives | ||||||
| Guide choices by changing default policy | Effective (two studies) | Not effective (one study only) | Effective (two studies) | |||
| Enable choice | Effective (one study only) | Inconclusive (two studies) | Not effective (one study only) | |||
| Provide information | Inconclusive (two studies) | Effective (four studies) | Effective (five studies) | Effective (three studies) | Effective (one study only) | Effective (three studies) |
| Do nothing or simply monitor the current situation | Inconclusive (one study only) | |||||
| Reorient government action | Effective (one study only) |
*Only levels with evidence from the included studies shown.
†No studies were found that had policies or interventions guiding choices through incentives.