The Measure of Stage of Readiness to Change: Some Psychometric Considerations

Previous research in the smoking cessation literature has shown that the key component of the transtheoretical model of change, the stage of readiness to change, is a valid independent measure (C. C. DiClemente & J. O. Prochaska, 1985; C. C. DiClemente et al., 1991; W. F. Velicer, J. S. Rossi, J. O. Prochaska, & C. C. DiClemente, 1996). Recently, however, other health service researchers (e.g., A. J. Farkas et al., 1996b) have begun to question the utility of this model; especially its predictive validity (e.g., A. J. Farkas et al., 1996a). However, no research to date has examined the reliability and stability of the stage of readiness to change measure. In this study, the longitudinal measurement of stage of readiness to change was treated as a quasi-simplex model (K. G. Joreskog, 1970). Estimates of the stability and reliability for 261 female smokers in a general community sample were obtained. Results indicate that the stage of change measure has desirable psychometric properties.