Application of Behavior Change Theory to the Development

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BEHAVIOR CHANGE THEORY
was generated in the same shop and at the same time that McBride and Peck (1970)
were developing a scientifically composed letter treatment from communications
theory.
However, the theory used by Jones (1997) and McBride and Peck (1970) to create their
treatment letters did not utilize many of the Early Stage elements (Appendix A-8). For
instance, the Jones letter that scored first in the use of General Stage methods fell to
tenth place in the use of Early Stage elements. McBride and Peck used one additional
Early Stage element in their low-threat letters than Jones applied to the soft-sell letter,
but that was still only half the number of General Stage elements they utilized.
Overall, the 42 letter treatments used, on average, 2.5 of six General Stage elements, 1.8
of five Early Stage methods, and 0.29 of five Late Stage techniques. However, the
various letters had a range of 1 to 6 General Stage elements, 0-4 Early Stage methods,
and 0 to 2 Late Stage techniques. Although the Early Stage methods were clearly
underutilized, the Late Stage techniques were all but ignored. No balanced treatment
letters were identified that used the majority of the elements available from all three
stages.
As with any new approach to an old problem, this review suffered from several
limitations. One constraint was the difficulty encountered in locating ageing warning
letters. The California Department of Motor Vehicles does not retain copies of old
letters, other than those collected and maintained by the Research and Development
Branch (R&D). Regrettably, some of the retained warning letters are undated, making
it impossible to determine the study in which they were used.
The opportunity to study the longitudinal warning letter data generated through the
California NOTES program for the decade beginning in 1985 and ending with the 1995
report was lost due to the failure to control the modification and dissemination of those
treatment letters. At this point, looking backwards, it is obvious that individual
members of a treatment cohort received different interventions but, since some archived
letters are not dated and others were changed during the subject selection period, it is
not possible to determine who received what treatments.
The evaluation of the treatment letters generated other concerns. Originally, a fivepoint,
goal attainment scale (GAS) was developed to evaluate the quality of the warning
letters in terms of the 16 TTM elements. However, the contents of the sentences did not
support the level of detail required in a five-point metric (-2 to +2). Although the scale
was later reduced to a more appropriate three-point GAS, two additional difficulties
arose. The first involves the translation of the meanings of the 16 TTM terms to the
actual words and sentences in the treatment letters. It was a more complex task than
originally anticipated and should have been preceded by a lengthy period of training
through practice. As experience with this assessment tool mounted, it became obvious
that more TTM elements were being identified in the later letters than in the earlier
ones. The length of the learning curve generated a recurring need to revisit and
reassess previously evaluated treatment letters.
The second difficulty involves reliability. The three points on the GAS scale need to be
anchored to a set of definitions or each element attached to a labeled, semantic