Simplified assessment of health behaviour determinants – self efficacy, subjective norm, and decisional balance

Objectives Assessment of the health behaviour determinants decisional balance (DB), self-efficacy (SE), and subjective norm (SN) usually relies on multi-item questionnaires (MIQs). These can be burdensome in large-scale or repeated-measure designs or simultaneous assessment of different health behaviours. This study developed and tested single-item questionnaires (SIQs) for DE, SE, and SN as an alternative. Design SIQs for DB, SE and SN were developed based on literature introducing the respective constructs into health behaviour research, on current MIQs and on responses received during a Delphi process regarding their content validity. Two studies (N=685 and N=206) compared the SIQs to MIQs. Assessments referred to regular exercise and three aspects of oral hygiene (OH) behaviour (i.e. regularity, training of skills and skilful performance). Study 3 (N=177) examined the stability of SIQs and their suitability for simultaneously assessing different but interrelated OH behaviours. Results Item characteristics of SIQs were in the range of MIQs. Convergence with MIQs ranged from r _tc =.284- r _tc =.736 depending on the determinant (lowest: DB) and the health behaviour. Re-test correlations ranged from r _tt =.475-r _tt =.763. ANOVAS revealed that individuals responded differently to different OH behaviours. Discussion This research offers initial evidence supporting the validity of the SIQs and their effectiveness in assessing multiple health behaviour determinants concurrently. The moderate re-test correlations fit the theoretical assumptions. The low convergences of the DB-SIQs may be explained by the features of the DB-MIQs, which assess pros and cons separately rather than the subjective weighing of arguments. Future research should further examine the SIQs’ validity.