To summarize the main points concerning sibling influence: 1. That siblings play a causal role in the development of aggressive behavior, in children's style of conflict behavior and in cooperative fantasy play is strongly suggested by recent research. 2. Marked problems in the sibling relationship are indicative of other problems, but a causal role for siblings is not established, other than for aggressive behavior. 3. Family factors are closely involved in the quality of sibling relationships--and thus in sibling influence, namely differential parental behavior, and the emotional climate of the family. That is, it is important not to consider the sibling relationship in isolation from other family relationships. 4. Studies of families under stress indicate heightened importance of these family factors. 5. It is likely, but not yet established, that later-born siblings are influenced by first-born in socio-cognitive development and gender identity. 6. Finally it should be noted that an important theme in current research on siblings is a concern with the question of why siblings develop to be so different from one another. It has been shown that the major source of environmental influence on the development of individual differences is within-family rather than between-family differences in experience (Plomin & Daniels, 1987). The different experiences each sibling may have within their relationship is one potential source of such differential environmental influence. Thus documenting the influence of siblings upon each other takes on added significance: By clarifying the extent and nature of this influence we will gain not only useful clinical information but illumination on a developmental principle of very general significance.

Sibling influences on childhood development.

• The efficacy of psychotherapy and the relative efficacy of different therapies are important issues that continue to receive attention in the literature. Questions about the efficacy of treatment usually are addressed by comparing groups that receive different treatment (or control) conditions. Comparisons are made on the basis of measures administered at the end of treatment and reflect the mean (average) amount of patient change across groups. Additional criteria to evaluate therapy and the relative value of different techniques include alternate measures of outcome and measures related to efficiency, cost, and patient evaluation of treatment. This article discusses such patient-related criteria as the clinical importance of therapeutic change, the proportion of patients who improve, and the breadth and durability of the improvements. Aside from these criteria, the evaluation of different therapies depends on the duration of different treatments, efficiency and costs of administering treatment, the financial and emotional costs to the patients, and cost considerations in relation to overall effectiveness. Finally, the acceptability of treatment to patients is an important consideration in evaluating treatment. Multiple criteria need to be used to evaluate treatment and the value of different treatments. The focus on narrowly circumscribed measures of average patient performance obscures the potential value of different treatments in relation to specific therapeutic and social goals.

Criteria for evaluating psychotherapy.

The present article reviews the behavioral parent training literature from 1975 to 1981. Both case studies and group investigations are included. The content and training methods of the parent intervention literature for children and adolescents are summarized. Methodological and clinical concerns are addressed, most notably generalization issues, the lack of parental observational data, the obtrusiveness of behavioral observation measures, and the need to identify critical characteristics of parents of clinic-referred children. The present status of this area is summarized and future research directions are suggested.

Henry Laviguer

Papers

The use of siblings as an adjunct to the behavioral treatment of children in the home with parents as therapists