Fidelity issues in secondhand smoking interventions for children

Abstract

This paper reviews methodological and theoretical fidelity of secondhand smoking (SHS) intervention studies (n = 29) that target protection of children in their home. In 2005, interventions were evaluated in terms of treatment fidelity according to guidelines provided by Borrelli et al. of the National Institutes of Health Behavior Change Consortium. The degree of fidelity was evaluated based on the percentage of criteria met; the inter-rater reliability based on percent agreement across independent raters was 0.78. Analysis indicated that studies with higher treatment fidelity were more likely to obtain statistically significant results (p = .003) with the average fidelity rating of 0.74 for statistically significant studies vs. 0.50 for statistically non-significant studies. Higher treatment fidelity was also significantly associated with being a more recent investigation (year 2000 or later), an efficacy as compared to effectiveness trial, more intensive as compared to less intensive intervention, a trial in the U.S. as compared to foreign nations, and having a theoretical basis. After taking all other variables into account, only treatment fidelity was significantly related to study outcome (p = .052). Ratings of treatment fidelity were ranked and compared to previous rankings based on 342 behavioral change interventions; the rank-ordered correlation between previous and current ratings was 0.84, although median fidelity ratings were 0.10 points lower in the previous than in the present study (0.52 vs. 0.62; intraclass correlation = 0.79). Improvements to the treatment fidelity evaluation guidelines were suggested, including the consideration of theoretical fidelity. Enhancing methodological and theoretical fidelity will speed identification of valid theoretical precepts that will, in turn, guide effective public health prevention programs.

Figure 1

Children’s reported exposure to mother’s exposure to cigarettes in the home (cigarettes per week), by self-report. From Zakarian et al. (2004). Used by permission.

Figure 2

Children’s urinary cotinine concentration (ng/ mL). From Zakarian et al. (2004). Used by permission.