An ordination approach to the quantification of smokers' readiness to change

The paper argues that the problem of estimating a "readiness-to-change": sc ore for smokers from processes of change measures is closely related to dat ing problems in archaeology. it amounts I finding a joint ordination of bot h smokers ("sites") and processes of change ("tools") ina common space, so that smokers be located close I to processes they use most, in some sense. Properties of Correspondence Analysis as a reciprocal averaging tech are fi rst briefly summarized, and its capability of recovering nonlinear structur es is recalled. Application to processes of change data in smoking cessatio n leads to a:solution which first arris is interpreted as a cognitive-behav ioral continuum. Processes are shown to be scaled in a way that is in good; convergence with longitudinal data previously reported (Prochaska et al., 1 991), and;subjects':locations to be significantly related to actual quittin g. Finally, it is shown how new responses profiles could be projected;on th e obtained solution to get a practical estimation of probability to quit.