• HEALTH PROMOTION
• PREVENTION
• PUBLIC HEALTH

Most clinicians and researchers have relied on patient or participant self-reported health information to overcome the constraints of eliciting these data in a clinic or laboratory setting. For example, time-dependent behaviours (eg, waking body temperature), or some sensitive or personal behaviour (eg, substance use or sexual behaviours) are difficult to directly observe in formal settings.1 Additionally, clinic-based or lab-based data collection may fail to capture how an individual's own ‘native’ circumstances and subjective experiences determine or modify a health behaviour.2 ,3 At the same time, it is important to safeguard the anonymity and confidentiality of self-reported information, as individuals may provide inaccurate data if they feel these elements have been breached.3

The use of electronic diaries has become an increasingly common data collection approach to maximise the ecological validity and the security of self-reported health information. Considerable diversity has evolved over the past decade in how electronic diaries are structured, in how frequently they are completed, and in the health phenomena they are used to study. As evidenced by their use to understand sexual behaviour,4 smoking cessation5 and substance use,6 asthma management7 seizure prediction,8 psychological state and disease symptomatology in old age,9 paediatric arthritis pain,10 and emotional regulation,11 electronic diaries can be a flexible and powerful way to intimately connect to the health experiences of others.

In this issue, Stalgaitis and Glick's12 systematic review of web-based diaries for understanding sexual risk …