Validity of the visual analogue scale as an instrument to measure self-efficacy in resuscitation skills.

Context: Self-efficacy is an important factor in many areas of medical education, including self-assessment and self-directed learning, but has been little studied in resuscitation training, possibly because of the lack of a simple measurement instrument.
Objective: We aimed to assess the validity of a visual analogue scale (VAS) linked to a single question as an instrument to measure self-efficacy with respect to resuscitation skills by comparing the VAS with a questionnaire and using known-groups comparisons.
Methods: We developed questionnaires to measure self-efficacy for a number of resuscitation tasks and for computer skills. These were compared with VASs linked to a single question per task, using a multi-trait, multi-method matrix. We also used known-groups comparisons of self-efficacy in specific professional groups.
Results: There was good correlation between the questionnaires and the VASs for self-efficacy for specific resuscitation tasks. There was a less clear correlation for self-efficacy for paediatric resuscitation overall. There was no correlation between self-efficacy for resuscitation and computer tasks. In specific professional groups, measured self-efficacy accorded with theoretical predictions.
Conclusions: A VAS linked to a single question appears to be a valid method of measuring self-efficacy with respect to specific well defined resuscitation tasks, but should be used with caution for multi-faceted tasks.