CHARM, funded by the RCUK Digital Economy Programme, used digital technologies to provide individuals with feedback about their own and others' sustainability- or health-related behaviours. The three-year project examined the potential for using the 'social norm' approach (informing people about the average behaviour of others) to make individual practices and behaviours more socially desirable.

The CHARM approach integrated practice theory (from sociology) and the social norms approach (from social psychology) to investigate novel uses of digital technologies to achieve behaviour change. Research in social psychology shows that our everyday activities are influenced by what we believe to be 'normal' behaviour. With this in mind, the social norms approach attempts to change behaviour in socially desirable ways by telling people what other people do. This approach had already been successfully employed to tackle/lower substance abuse and address sustainability issues such as recycling, hotel towel reuse and electricity consumption.

Practice theory emphasises the habitual, routine nature of individual behaviour and the ways in which it is shaped by the broader sociotechnical context within which it occurs. It suggests that behaviours are best understood as products of everyday, taken-for-granted practices such as those connected with heating, lighting, cleaning, travel and recreation.

The CHARM approach was distinguished by its use of digital technologies, smart-phones, the internet, energy monitors, accelerometers, GPS and social networking applications to provide participants with sophisticated social norm feedback. In addition, in CHARM the quantitative behavioural data collection and questionnaires typical of the social norm approach were complemented by ethnographic interviews and focus groups that provide in-depth understanding of the sociotechnical contexts of behaviour. This novel approach was applied in three case studies: 1) the Home Energy Study; 2) bActive, the active lifestyle study, and 3) iGreen, a social networking study.