The Decision Making Control Instrument to Assess Voluntary Consent

Abstract

Background. The decision to participate in a research intervention or to undergo medical treatment should be both informed and voluntary. Objective. The aim of the present study was to develop an instrument to measure the perceived voluntariness of parents making decisions for their seriously ill children. Methods. A total of 219 parents completed questionnaires within 10 days of making such a decision at a large, urban tertiary care hospital for children. Parents were presented with an experimental form of the Decision Making Control Instrument (DMCI), a measure of the perception of voluntariness. Data obtained from the 28-item form were analyzed using a combination of both exploratory and confirmatory factor analytic techniques. Results. The 28 items were reduced to 9 items representing 3 oblique dimensions: Self-Control, Absence of Control, and Others’ Control. The hypothesis that the 3-factor covariance structure of our model was consistent with that of the data was supported. Internal consistency for the scale as a whole was high (0.83); internal consistency for the subscales ranged from 0.68 to 0.87. DMCI scores were associated with measures of affect, trust, and decision self-efficacy, supporting the construct validity of the new instrument. Conclusion. The DMCI is an important new tool that can be used to inform our understanding of the voluntariness of treatment and research decisions in medical settings.