peer reviewed ; People are social beings. We look at others to determine for ourselves what is normal. But the image we have of others is often wrong. Especially when it comes to alcohol. We often overestimate our unhealthy behaviour and underestimate the healthy behaviour of our peers (compared to ourselves). This difference in idea and reality is used in the SNA project in the Euregio Meuse-Rhine (EMR) described here. The starting point here is that health behaviour is determined, among other things, by social norms. SNA is a method that can be used in the context of addiction prevention (alcohol prevention) and is based on the idea that the social norm influences the formation of social behaviour. People often misjudge the social norm, by overestimating or underestimating it, which can lead to unhealthy choices. Through SNA, the aim is to inform people about the actual behaviour within a social group and thus influence people's social norm. To be effective, the message using SNA must be perceived by the target group as relevant and related to the norms of their group. To achieve this, the data must come from the target group itself. In the EMR, demographic developments lead to a growing number of older people with alcohol-related health problems. Therefore, in our region, an online survey was conducted with a large number of 55+ persons (n=3,122) to map the actual use and the expected use of peers.55+ persons in the EMR overestimate the expected alcohol use of others compared to the actual use. On average, the German regions overestimated the alcohol use of others (in comparison with actual use) to a greater extent than the Dutch and Belgian regions, where no significant differences were seen between the regions. Older seniors (75+) overestimate less than younger seniors (55-74). Women overestimate more than men. ; euPrevent SNA