The same, only different: Smartphone-based dietary Ecological Momentary Assessment tools vary in complexity, usability, and active information processing

Ecological Momentary Assessment (EMA) has become popular to assess dietary intake in real life and real time. Available tools differ substantially in the type and number of implemented features including features to assess what and how much was consumed. The features require qualitatively different input that might exert differential impact on the participants’ cognitions and behaviours while taking part in the study. This preregistered online experimental study aimed to test whether more complex dietary assessment tools, indicated by the type and number of assessment features, induce more active information processing. A total of 373 participants (65.4% female; mean age 30.4 years) were randomly allocated to viewing one of eight EMA protocol mock-ups, each describing a food tracking process verbally and using screenshots. Afterwards, they rated the protocol in terms of its complexity (manipulation check), active information processing and its potential impact on eating-related cognitions, intentions and eating behaviour change. The eight EMA protocols differed regarding perceived complexity, i.e. protocols with more tracking features were perceived as more complex compared with ones with fewer tracking features. EMA protocols that were perceived to be more complex were also perceived to induce more active information processing. However, there were no differences regarding perceived impact on eating-related cognitions, intentions, and behaviour. These differences in complexity and usability may influence compliance and study results. Researchers thus need to carefully select the appropriate EMA protocol for their study to balance the need for collected information with the need for high compliance.