, 2005). Overall, the kappa values in Trichostatin A (TSA) our study were moderate but the percent agreements were high. It has been suggested that kappa values are influenced by the bias and prevalence of the outcome (Banerjee & Fielding, 1997), such that a high prevalence index (when the prevalence of a positive rating is very high or very low) results in lower kappa values (Sim & Wright, 2005). In our study, the prevalence of nonsmoking was very high, and the bias, or the extent to which raters disagree, was also low, leading to the moderate kappa values. Our study had several limitations. First, the mothers�� self-reported smoking status was not biochemically validated. Second, smoking data from fathers were limited, so we could not reliably compare father and adolescent reports.

Third, the mother and adolescent data were not collected concurrently. However, maternal data were available from two timepoints, one before and another after the adolescents�� reports on their mothers�� smoking behavior. Fourth, unfortunately while we have detailed data from the mothers about their smoking behavior (e.g., self-reported level of nicotine dependence, number of cigarettes smoked per day, when first cigarette is smoked during the day), we did not have similar information from the children regarding the mothers�� smoking behavior. Therefore, we are unable to address the important issue of whether adolescents can provide more detailed information about their parents�� smoking behaviors, other than whether or not they do/did smoke.

In conclusion, the results of this study indicate that adolescent proxy reports on maternal smoking are accurate, suggesting that adolescent reports on mothers�� smoking behavior can be used as a proxy to obtain data if the mothers�� self-report data are not available. Our results further suggest that when reports are not collected concurrently, it may be more reliable to use self-report data that were obtained from the mothers prior to the proxy report obtained from their adolescents, rather than the other way around. In addition, in future studies, if the adolescent��s proxy report is used in lieu of the mother��s report, whenever possible, analyses should control for the adolescent��s age and experimenter status. Finally, the results suggest that latent variable modeling is warranted.

Funding This research is supported by the National Cancer Institute grants CA105203 (MRS), CA093592 (CJE), CA123208 (CJE), and CA126988 (AVW), by funds collected pursuant to the Comprehensive Tobacco Settlement of 1998 and appropriated by the 76th legislature to the University of Texas M.D. Anderson Cancer Center and by the Caroline W. Law Fund Carfilzomib for Cancer Prevention. Declaration of Interests None declared. Supplementary Material [Article Summary] Click here to view.