Application of Behavior Change Theory to the Development

BEHAVIOR CHANGE THEORY
these reasons, it is very difficult to attribute causality to an independent variable. If
there is a systematic difference in a dependent variable associated with levels of an
independent variable, the two variables may be related, but no causal relationship is
implied (Tabachnick & Fidell, 2001). Eventually, a judgment will need to be made as to
whether that statistical association represents a cause-effect relationship between the
independent and dependent variables. Unfortunately, this kind of judgment requires
inferences that reach beyond the data from any single study (Hennekens & Buring,
1987).
Uncertainty in the cause and effect association complicates the process for establishing
causality; a critical component in an administrator’s decision to institute research-based
policy. Since the data from a single quasi-experimental study is insufficient for this
purpose, more extensive criteria have evolved to support the claim of causal inference.
They include the following:
• Strength of Association: The greater the magnitude of the effect size, the less likely the
association is spurious.
• Consistency: Repeated observation of an association in independent studies.
• Temporality: Documentation that cause precedes effect in time.
• Response Relationship: Outcome relates to the intensity, frequency, or duration of a
treatment or exposure (or a combination of these).
• Coherence of Evidence: The observed relationship is consistent with what is known
about underlying theory, models, natural history, or biology.
Given a nonexperimental traffic safety research agenda and the attendant causal
indeterminacy problem, the Transtheoretical Model offers several advantages to traffic
safety research, including:
• Face Validity: The TTM contains motivational components familiar to those
identified by traffic safety researchers who consider them to be efficacious, even
essential treatment elements. Therefore, acceptance of the TTM would be enhanced
due both to familiarity and an intuitive understanding of its precepts.
• Outcome and Recalcitrance: The TTM has consistently demonstrated significant
results even with intractable subjects and immutable behaviors. Consequently, the
TTM provides a blueprint for the development of better treatments capable of
producing larger effect sizes even with the most recalcitrant negligent operators.
Large effect sizes are imperative when conducting quasi-experimental research.
• Research Agenda: Causal indeterminacy demands vision, a mental image of the
succession of studies needed to establish consistency through corroborative
research. TTM research has blazed that trail and those efforts could serve as a
compass for future traffic safety research.
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