Читать книгу Abnormal Psychology - William J. Ray - Страница 139

Although researchers seek to design studies to rule out alternative hypotheses, they cannot consider every possibility. When a study is performed in different laboratories with different participants, a process referred to as replication, we can have more certainty that the results found reflect the true nature of what we are studying. Thus, scientists seek to find a number of different studies from different laboratories that answer the same research question. For example, various studies from around the world have shown structural brain differences in individuals with schizophrenia including enlarged ventricles in the brain (Faludi & Mirnics, 2011). A number of journals, such as Clinical Psychology Review and Psychological Bulletin, are designed to publish reviews of research in the field.

replication: the process whereby a study is performed in different laboratories with different participants and obtains the same results

Once the literature in a particular area has been reviewed, it is possible to examine statistically the results of all the studies taken together. This technique is referred to as meta-analysis. Meta-analysis is a statistical technique for combining a number of studies to improve the reliability of the results. For example, a large number of studies have examined depression and how it can be treated with cognitive behavioral therapy (Butler, Chapman, Forman, & Beck, 2006). With a meta-analysis, it can be asked, what if we consider all of these studies to be one study. Then we could calculate the common effect size of all of the available studies. A similar meta-analysis was performed to examine the effectiveness of interpersonal psychotherapy for depression (Cuijpers et al., 2011). While the use of meta-analysis is often invaluable, the LENS below points to a potentially complicating factor when undertaking such a review of previously published studies.

meta-analysis: statistical examination of the results of studies taken together and treated as one study

Lens