Intraclass Correlation among Common Measures of Adolescent Smoking: Estimates, Correlates, and Applications in Smoking Prevention Studies

Murray, David M.; Rooney, Brenda L.; Hannan, Peter J.; Peterson, Arthur V.; Ary, Dennis V.; Biglan, Anthony; Botvin, Gilbert J.; Evans, Richard I.; Flay, Brian R.; Futterman, Robert; Getz, J. Greg; Marek, Pat M.; Orlandi, Mario; Pentz, Mary Ann; Perry, C.; Schinke, Steven P.

doi:10.1093/oxfordjournals.aje.a117194

Cited by 114 publications

(71 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, a few studies showed that schoollevel intraclass correlations for smoking and other health behaviors ranged from 0 to 0.075. [48][49][50] Intraclass correlation coefficients in relevant schoolbased studies often are small, 51 which enhances our confidence in our treatment effects.…”

Section: Discussionmentioning

confidence: 94%

Effects of Physical Activity on Teen Smoking Cessation

et al. 2011

View full text Add to dashboard Cite

OBJECTIVE: To understand the influence of physical activity on teen smoking-cessation outcomes. METHODS: Teens (N = 233; 14–19 years of age) from West Virginia high schools who smoked >1 cigarette in the previous 30 days were included. High schools with >300 students were selected randomly and assigned to brief intervention (BI), Not on Tobacco (N-O-T) (a proven teen cessation program), or N-O-T plus a physical activity module (N-O-T+FIT). Quit rates were determined 3 and 6 months after baseline by using self-classified and 7-day point prevalence quit rates, and carbon monoxide validation was obtained at the 3-month follow-up evaluation. RESULTS: Trends for observed and imputed self-classified and 7-day point prevalence rates indicated that teens in the N-O-T+FIT group had significantly higher cessation rates compared with those in the N-O-T and BI groups. Effect sizes were large. Overall, girls quit more successfully with N-O-T compared with BI (relative risk [RR]: >∞) 3 months after baseline, and boys responded better to N-O-T+FIT than to BI (RR: 2–3) or to N-O-T (RR: 1–2). Youths in the N-O-T+FIT group, compared with those in the N-O-T group, had greater likelihood of cessation (RR: 1.48) at 6 months. The control group included an unusually large proportion of participants in the precontemplation stage at enrollment, but there were no significant differences in outcomes between BI and N-O-T (z = 0.94; P = .17) or N-O-T+FIT (z = 1.12; P = .13) participants in the precontemplation stage. CONCLUSIONS: Adding physical activity to N-O-T may enhance cessation success, particularly among boys.

show abstract

Section: Discussionmentioning

confidence: 94%

Effects of Physical Activity on Teen Smoking Cessation

et al. 2011

View full text Add to dashboard Cite

show abstract

“…Less has been written, however, about the intraclass correlation as a parameter of interest with utility for investigators. Murray et al surveyed community-based studies of smoking interventions in classrooms of students and described variations in intraclass correlation within classrooms across the studies (22). Using data from the Health Survey for England, Guillford et al reported several levels of intraclass correlation from the district health authority to the household (23).…”

Section: Discussionmentioning

confidence: 99%

Measuring the Efficacy of a Quality Improvement Program in Dialysis Adequacy with Changes in Center Effects

Fink

Zhan

Blahut³

et al. 2002

Journal of the American Society of Nephrology

View full text Add to dashboard Cite

Abstract. End-stage renal disease (ESRD) patients treated with hemodialysis have a high mortality rate, which is largely due to inadequate dialysis. Dialysis adequacy, measured by the urea reduction ratio (URR), tends to be correlated within dialysis facilities with wide variations in average center adequacy. These are characteristics of a center effect, which can have an important impact on dialysis adequacy. This study measured the center effect observed in an ESRD Network before and after a successful quality improvement project (QIP). URR values were recorded on patients sampled from 196 facilities in ESRD Network 6 before (pre-QIP, n ϭ 5309) and after (post-QIP, n ϭ 5753). These data was used to determine the within center correlation () of individual URR values and between center variation in aggregate URR values in both samples. The overall mean URR improved from the pre-to post-QIP sample (mean URR 64.7 Ϯ 0.1 versus 69.8 Ϯ 0.1, respectively; P ϭ 0.001). There was a high degree of within center correlation in dialysis adequacy across the facilities, which significantly diminished post-QIP (, 0.15 [95% CI, 0.12 to 0.18] versus , 0.06 [95% CI, 0.04 to 0.08]). The between center variation in mean URR also declined from the pre-QIP to the post-QIP sample (SD, 3.6 versus 2.8). In conclusion, there is a center effect on dialysis adequacy measurable in an ESRD Network, which diminishes after a successful QIP; therefore, when implementing a QIP to improve dialysis adequacy, changes in the center effect should be considered a potential indicator of the efficacy of the intervention.The health and well being of patients with end-stage renal disease (ESRD) continues to be dismal (1), and much of this poor outcome can be attributed to inadequate treatment with hemodialysis, which is the renal replacement therapy for a majority of patients with this disease (2-6). Although there are national standards for adequate dialysis (7), there are several barriers to achieving these mandated treatment goals. Efforts to improve dialysis adequacy have emphasized correcting patientspecific factors that are linked to inadequate dialysis (8 -11). It is likely that factors at the center level also contribute to the shortcomings in dialysis treatment.When present, such center effects on dialysis adequacy results in patients from the same dialysis unit receiving similar doses of dialysis compared with patients from different centers. A high degree of intrafacility or within center correlation in dialysis adequacy would suggest not only that patients are influenced by a center effect but also that the patients with poor care were not randomly distributed among dialysis facilities. A related finding to an observed center effect in a population of dialysis patients is that aggregate achieved adequacy in centers is widely variant. The between center variation in performance results in some centers having overall adequacy exceeding mandated goals while others underperform, which is also consistent with the possibility that poorly dialyzed pa...

show abstract

“…24 We assumed an intracluster correlation of ρ = 0.01 based on a comparison with the mean ρ found by Murray and associates 27 of ρ = 0.006 in examining adolescent smoking behaviour. We also adjusted for a potential drop-out and noncompliance rate in the intervention group and a contamination rate in the control group (R o = 0.10).…”

Section: Methodsmentioning

confidence: 99%