Publication bias in meta-analysis of single-case research designs based on hierarchical linear models.

2014 Fiscal Year Final Research Report

• Project/Area Number: 24730530
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Educational psychology
• Research Institution: Joetsu University of Education
• Principal Investigator: OKUMURA Taichi 上越教育大学, 学校教育研究科(研究院), 准教授 (90547035)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 階層的線形モデル / 単一事例実験 / メタ分析

Outline of Final Research Achievements

This study examined the factors and degrees of publication bias when single-case research design data are synthesized by the hierarchical linear models (HLM). Results can be summarized into the following three points: (1) Distributions of effect sizes of single-case designs that were reported in Japan were distorted, implying that the publication biases existed in these studies. (2) When subjects are screened by their pretest scores, treatment effects tend to be overestimated by the regression to the mean effect, and even non-effective treatments can be evaluated as largely effective. (3) When publications of the single-case studies depend on the statistical significance of the treatments and only published cases are used for meta-analyses by the HLM, originally non-effective treatments can be evaluated as if they were considerably effective ones.

Free Research Field

心理統計学