@article{e582da66198d4af79a1607c7087e15e3,
title = "Testing for group membership effects during and after treatment: The example of group therapy for smoking cessation",
abstract = "Behavioral interventions often are administered in groups, yet the effects of group membership rarely have been evaluated. The current research examined 33 groups of clients (M = 5.5 clients per group, SD = 2.5) volunteering for a group smoking cessation intervention. The intervention consisted of 6 group therapy sessions over an 11-day period. Attendance at the sessions and smoking behavior during the 11-day period were the dependent variables. Hierarchical linear modeling (HLM) revealed a statistically significant (p < .05) degree of interdependence among group members (intraclass correlation = .44 and .32 for attendance and smoking, respectively). Groups were characterized disproportionately by high attendance and infrequent smoking or low attendance and relatively frequent smoking, with fewer moderate groups than would be expected by chance. Group membership effects dissipated within a month following treatment. These findings suggest the need for assessing such effects and for future research examining their causes.",
author = "Herzog, {Thaddeus A.} and Lazev, {Amy B.} and Irvin, {Jennifer E.} and Juliano, {Laura M.} and Greenbaum, {Paul E.} and Brandon, {Thomas H.}",
note = "Funding Information: Behavioral interventions often are administered in groups, yet the effects of group membership rarely have been evaluated. The current research examined 33 groups of clients (M = 5.5 clients per group, SD = 2.5) volunteering for a group smoking cessation intervention. The intervention consisted of 6 group therapy sessions over an 11-day period. Attendance at the sessions and smoking behavior during the 11-day period were the dependent variables. Hierarchical linear modeling (HLM) revealed a statistically significant (p < .05) degree of interdependence among group members (intraclass correlation = .44 and .32 for attendance and smoking, respectively). Groups were characterized disproportionately by high attendance and infrequent smoking or low attendance and relatively frequent smoking, with fewer moderate This research was supported by American Cancer Society grant JFRA389, American Heart Association-New York grant 92-024GB, and National Institute on Drug Abuse grant DA 10484. The therapy sessions were conducted at the State University of New York at Binghamton. We thank Mark Goldman and Mark Hallahan for their helpful comments on earlier drafts. We also thank the doctoral students who served as therapists and research assistants on the study (Amy Copeland, Edward Quinn, Brad Collins, and Jacqueline Kloss), as well as the many undergraduate research aides who worked on the project.",
year = "2002",
doi = "10.1016/S0005-7894(02)80004-1",
language = "English (US)",
volume = "33",
pages = "29--43",
journal = "Behavior Therapy",
issn = "0005-7894",
publisher = "Elsevier Inc.",
number = "1",
}