Glendon Casto

The Quantitative Synthesis of Single-Subject Research Methodology and Validation

This article describes procedures recently employed for the quantitative synthesis of single-subject research literature in special education. First, the need for objective, systematic review procedures is discussed. Second, previous approaches for quantitative evaluation of outcomes of single-case research designs are reviewed. Third, procedures employed by the present authors are outlined using examples from recent synthesis efforts. Finally, implications for future reviews of single-subject research are described.

The Efficacy of Early Intervention Programs: A Meta-Analysis

This article reviews primary research studies investigating the efficacy of early intervention with handicapped preschoolers. Meta-analysis techniques were employed to integrate statistically the findings from 74 studies. Findings indicate that: (a) early intervention with handicapped populations produces a positive sizeable effect size; (b) longer, more intense programs are associated with efficacy; and (c) little support was found for commonly held beliefs about early intervention, such as the importance of age at start and the degree of parental involvement. Implications for future research are discussed.

Handicapped Students as Tutors

A meta-analysis was conducted on available research documenting effectiveness of handicapped students as tutors of other students. Nineteen articles yielding 74 effect sizes were located. Results indicated that (a) tutoring programs were generally effective; (b) tutees generally gained more than tutors; and (c) tutor and tutee gains on self-concept and sociometric ratings were small, while gains on attitude measures were larger. Implications for instruction and further research are given.

An integrative review of early intervention efficacy studies with at-risk children: Implications for the handicapped

Results of 162 early intervention efficacy studies with disadvantaged, at-risk, and handicapped children were analyzed to draw conclusions about the efficacy of early intervention, identify variables which covary with effectiveness, and identify areas for future research. Because of the scarcity of data and methodological problems with efficacy studies with handicapped children, much of the paper focuses on conclusions drawn from research with disadvantaged and at-risk populations and the implications of those data for handicapped children. It is concluded that early intervention has substantial immediate benefits for at-risk and disadvantaged children. What few data are available about the effects of parental involvement, age at which intervention starts, training of the intervenor, and maintenance of effects are often contrary to what many people have assumed. Methodological suggestions to improve future early intervention research are discussed.

Family support in the home: Programs, policy, and social change.

The need for a coordinated national policy on family support in the home is discussed. First, the history of home visiting programs is reviewed. Then, recommendations for practice, training, and research in family support programs are presented. A discussion of the impact of new federal initiatives on family support programs and research demonstration efforts follows.

Parent Involvement in Infant and Preschool Programs.

An analysis of parent involvement in early intervention programs was conducted as part of a review of literature on the efficacy of early intervention with disadvantaged, at-risk, and handicapped preschoolers. The evidence to date suggests that there is little support for the position that involvement of parents leads to more effective intervention programs. The meta-analysis also demonstrated that there is little research which addresses the issue of parental involvement with handicapped children. Suggestions for future research are included.

An Analysis of Special Education Early Childhood Projects Approved by the Joint Dissemination Review Panel

Twenty-one early intervention projects, which have been approved by the Joint Dissemination Review Panel for national dissemination, were analyzed to determine their characteristics and the strengths and weaknesses of their research designs, as well as to draw conclusions about the efficacy of early intervention. It was found that early intervention projects approved by the Joint Dissemination Review Panel are consistent with prevailing notions that intervention programs should involve parents, should start as early as possible, and should utilize structured intervention programs. It was also concluded that these intervention programs had made substantial contributions to the field in terms of demonstrating the feasibility of early intervention, developing and disseminating curriculum materials and assessment instruments, and providing methods of intervention. Due to the frequency of serious methodological weaknesses, however, one can conclude little about the efficacy of early intervention from these project reports. Suggestions are made for improving future early intervention efficacy research.

Learning From Reviews of Early Intervention

Reviews of the literature are frequently advocated to advance knowledge in the social sciences. Unfortunately, most reviewers do not explicitly consider or attempt to learn from what previous reviewers of the same or closely related topics have done. This omission is inconsistent with good scientific practice and is significantly detrimental to advancing knowledge. Using 52 previous reviews of the early intervention efficacy literature as an example, this article demonstrates the value of systematically considering previous reviews before initiating a new review. The results establish a foundation that should be particularly helpful to future reviewers of the early intervention efficacy literature and demonstrate a process that should be used by reviewers in all areas.

Reply to Owen White

The response of Owen White generally supports the notion of computing objective study outcomes for the purpose of reviewing single-subject research. He suggests, however, that our model is not sensitive to trends and proposes a model for computing percentage of nonoverlapping data based upon consideration of baseline trends. We respond that although such a procedure has theoretical merit, it has little practical utility due to the limited number of observations typically found in single-subject baselines; furthermore, when reliable and substantial baseline trends are found, interpretability of study outcomes is seriously limited.

MOTHERS‘ PERCEPTIONS OF THEIR CHILDREN'S SUPPLEMENTAL CARE EXPERIENCE: Correlation With Spousal Relationship

Mothers whose children were enrolled in day care and home-based care were asked to rate the care environment and assess its effects on their childrens development, on parent-child relationships, and on spousal relationships. Significant differences in perceptions between the two groups of mothers and significant associations between the parent-child/marital and the supplemental care systems were revealed.