Group Dynamics: Theory, Research, and Practice Call for Papers in Statistical Methods in Group Psychology and Group Psychotherapy Group Dynamics, Theory, Research, and Practice publishes state of the art research on group psychology and group psychotherapy. The study of people nested in small groups represents unique challenges to the researcher. Group members interact with each other, they share common experiences within their group that may be different across groups, and each group may be affected by different compositions and histories. These factors make groups and group research interesting, but they also complicate the analyses of grouped data. Group Dynamics invites authors to submit papers that address salient issues related to the design and analyses of grouped data. The focus will be on conceptual issues that are addressed by the method, and on its practical applications. As such, each paper should be structured to include the following: (1) a conceptual introduction of the issues being addressed and their importance to group research, (2) a concrete running example of real or simulated data and their analyses to make the concepts and data analytic approach come to life, (3) instructions or suggestions on which relevant findings to report and how (e.g., parameters, variance components, model fit statistics, effect sizes, etc.), (4) practical suggestions on how and under what circumstances to apply the method, (5) common pitfalls or problems in applying the method and/or interpreting findings, (6) a short annotated bibliography of software, web sites, and key articles or chapters, and (7) if appropriate, online supplementary material with syntax, computer codes, or macros. Equations or figures should be fully described and all parameters should be clearly and concretely defined using the running example. Emphasis should be place on interpreting the statistical findings in the context of the running example (data in the running example does not need to be new as it is primarily being used as illustration). The manuscript should be: aimed at the level of a new researcher or a graduate student who will use the paper to guide them in their own data analyses; or aimed at readers who may use the paper to help them understand and evaluate group research. Authors might assume for example that the reader has only basic knowledge of statistical concepts (i.e., regression equations) and of group psychology and psychotherapy. Papers should be no more than 30 pages in length, not including online supplementary material. All submissions will be peer reviewed. This special issue of Group Dynamics on statistical methods will bring together in one volume papers that will serve as a reference for authors, reviewers, and students who wish to conduct and evaluate state of the art group psychology and group psychotherapy research. Deadline for submissions is September 15, 2015. Submissions can be made through the journal submission portal on the American Psychological Association web site. Authors should indicate in the cover letter that the manuscript is intended for the special issue on statistical methods in group psychology and group psychotherapy. Authors are encouraged to contact Giorgio A. Tasca (gtasca@toh.on.ca) to discuss the suitability of a potential topic for submission.