Application of Behavior Change Theory to the Development

BEHAVIOR CHANGE THEORY
Finally, the positive accident reductions due to the interaction of the questionnaire with
the intimacy dimension (F = 3.10, p < 0.10) can be viewed in a similar fashion to the
delayed effect of treatment by intimacy.
Epperson and Harano, 1975
RATINGS:
Research Design: 20/24
Standard Form Letter: 6/33
Low Threat/High Intimacy: 24/33
Pamphlet: 15/33
Reinforcement Letter: 7/33
In this study, Epperson and Harano (1975) analyzed the effectiveness of two types of
warning letters (standard and low threat/high intimacy), an informational pamphlet,
and a follow-up reinforcement letter (Appendices B-11 to B-14). A total sample of
16,513 drivers throughout California was selected from the central driver record files
located at DMV headquarters. These drivers became eligible for the warning letter
program by accumulating three negligent operator points within the previous 12
months. The subjects were assigned to the various treatment groups in a functionally
random selection process based upon the final digit of the driver’s license number. The
alpha level was set at .10.
This study met five of the six quality standards: the participation rate exceeded 70%; a
random assignment procedure was used; no significant differences were found among
the groups for sample size, percent males, percent married, age, or prior collisions and
convictions; the researchers apparently were blinded to the randomization schedule;
and, treatment preceded outcome. However, the study did not utilize a no-treatment
control group.
The research design assigned one-half of the eligible subjects (16,513) to the low
threat/high intimacy condition and the other half to the standard warning letter
treatment. One-half of each of those two groups received a pamphlet with the
treatment. One-half of the pamphlet/treatment combinations (2) were mailed to groups
(4) with clean records while the other half went to those groups (4) with convictions of
their driving records. An identical distribution was used with the nopamphlet/treatment
combinations. Finally, half of the clean record groups (4) received
a follow-up letter.
Concerning the TTM, the low threat and high intimacy letter (Appendix B-12) used all
six general strategies, three of five early stage methods, and no late stage techniques
(Table 9). Four strategies (express empathy, strengthen self-efficacy, dramatic relief,
and environmental reevaluation) were scored as providing, “more than expected
treatment/TTM match (+1)”. Scores for this version of the warning letter were identical
to the low threat and high intimacy letter used in the McBride and Peck (1970) study,
which served as a model. However, the two low threat and high intimacy letters were
not identical. Although the Epperson and Harano (1975) letter added a single, short
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