Guideline 1: Goal of the Study, Population, and Type of Study
This study, "Evaluation of Smoking Characteristics among Community-Recruited Daily Smokers with and without Posttraumatic Stress Disorder and Panic Psychopathology," by Erin Marshall and associates (2008) was found as an online article; it had been reprinted from a journal. The study's goal was to examine whether several cigarette smoking related variables (e.g. nicotine dependence, smoking rate, quit history, severity of symptoms, etc.) significantly differed depending upon whether smokers had posttraumatic stress syndrome (PTSD), panic disorder (PD), nonclinical panic attacks (PA), or no current Axis I psychopathology (controls). The population consisted of people responding to recruitment ads that met several subject selection criteria related to smoking, and to diagnostic criteria concerning PD, PTSD, PA and No current Axis I psychopathology. The nature of the study was descriptive comparison which seeks to describe variables of interest and possible differences in two or more groups and then apply the research findings to the sample population (see: Goodwin, 2007).
The primary author, E. C. Marshall, is a professor at the University of Vermont's Department of Psychology who has conducted a good deal of research on panic attacks and other anxiety disorders. Moreover, the Journal of Anxiety Disorders in which the study was published is a peer-reviewed journal. Both the author's credentials and the peer-reviewed journal add to the credibility of the study and its findings.
The subjects in this sample were all volunteers in the sense that they 'self-recruited' by answering ads and so forth. Goodwin (2007), in a discussion of selection bias, notes that volunteers can sometimes add bias to a given sample because people who volunteer to participate in research are often different than those who do n
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