Application of Behavior Change Theory to the Development

BEHAVIOR CHANGE THEORY
A review of the literature exposed a rich history of ideas traffic safety professionals had
expressed to improve the effectiveness of warning letters. McBride and Peck (1970)
advocated systematic feedback, intimacy, empathy and contingency management to
enhance the content of warning letters. Li (1980) recommended the inclusion of a
statement reinforcing the importance of personal responsibility, and also noted the need
to raise the consciousness of negligent drivers. Carpenter and Peck (1980) offered
choice in their probation by mail study. Ayers (1980) concurred with the need to
express empathy as a means to motivate the drivers to accept the message contained in
the warning letter. Kaestner et al. (1965) thought it was important to make an attempt
to strengthen the driver’s sense of self-efficacy. Epperson and Harano (1975)
recognized the necessity of providing information regarding the nature and risk of
unsafe driving behaviors. And, Campbell (1959) recommended the use of contingency
management.
Warning letters are not new; Michigan, for instance, has been issuing them since 1940
(Hayes, 1969). What has been missing is a theory or model of behavior change that
incorporates the observations of past traffic safety professionals with current
knowledge generated from studies conducted within the field of transformational
psychology.
The Transtheoretical Model (TTM) of change (Prochaska & DiClemente, 1982, 1984)
satisfies these requirements and, in addition, provides results from a research agenda
that has steadfastly evaluated the effectiveness of the theory’s elements. Over the past
half-century, traffic safety researchers independently identified 11 of the 16 general,
early, and late stage strategies as important components to be included in advisory
letters. These 16 TTM elements provided a standard basis for evaluating the quality of
the warning letters reviewed for this report.
The factored total quality scores for the 42 treatment letters demonstrate the fact that
traffic safety researchers were not guided by a single theory of change (Appendix A-4).
The Epperson et al. (1974) low threat/high intimacy letter earned the highest factor
score, 44 of 57. Jones (1997) achieved a similar score of 43 for the “soft-sell” letter.
Interestingly, Jones’ standard treatment letter ranked 37 th , having scored only 27 points
out of a possible 57. The Epperson et al. (1974), Jones (1997) and McBride and Peck
(1970) studies all demonstrate that the soft-sell or intimacy component of a treatment is
a reflection of the number and type of TTM elements incorporated into the
communication. For instance, Jones’ soft-sell letter scored 18 for its use of General
elements while the standard letter scored 3.
The letters composed by McBride and Peck were similarly differentiated between the
highly scored low threat letters and the other two. Obviously, a major part of what
these authors refer to as threat and intimacy are represented in the General elements of
the TTM.
There also appears to be a relationship between the General elements of the TTM and
the components of communications theory. It is probably not coincidental that the five
letter treatments that used the largest number of General elements (Appendix A-7) were
all developed from communications theory. In addition, the sixth study (Marsh, 1969)
39