Idiographic methods: basic principles, opportunities and challenges
Theories of behaviour change and health behaviour change interventions are usually tested in conventional between-participant designs. However, most of these theories and interventions ultimately focus on within-participant change. This mismatch between the idiographic basis of most theories and intervention causal models and the nomothetic approach of the methodologies typically used to evaluate them is fundamentally problematic. Appreciation of this is fueling the growing interest in N-of-1/within-participant methods, yet there is currently a shortage of opportunities to learn about these approaches. This talk introduced idiographic methods to test a) predictors of behavioural outcomes and b) evaluate interventions using experimental designs, including practical examples; and highlighted behavioural issues most amenable to idiographic investigations.