Previous research in the smoking cessation literature has shown that t
he 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. E Velicer,
J. S. Rossi, J. O. Prochaska, & C. C. DiClemente, 1996). Recently, ho
wever, other health service researchers (e.g., A. J. Farkas et al., 19
96b) have begun to question the utility of this model; especially its
predictive validity (e.g., A. J. Farkas et al., 1996a). However, no re
search to date has examined the reliability and stability of the stage
of readiness to change measure. In this study, the longitudinal measu
rement of stage of readiness to change was treated as a quasi-simplex
model (K. G. Joreskog, 1970). Estimates of the stability and reliabili
ty for 261 female smokers in a general community sample were obtained.
Results indicate that the stage of change measure has desirable psych
ometric properties.