The Effectiveness of Workplace Support Interventions in Increasing Long-Term Employment Retention Among Adults with Intellectual Disabilities: A Quantitative Meta-Analysis

Abstract

Employment is widely recognized as a fundamental determinant of social inclusion, economic independence, and quality of life. Despite international commitments to inclusive employment and disability rights, adults with intellectual disabilities continue to experience significantly lower employment and job retention rates than the general workforce. While numerous workplace support interventions—including supported employment, job coaching, customized employment, employer education, workplace accommodations, and structured transition programs—have been implemented to improve employment outcomes, evidence regarding their long-term effectiveness remains fragmented across different study designs, intervention models, and geographical contexts. Consequently, a quantitative synthesis is necessary to determine the overall effectiveness of these interventions in promoting sustained employment among adults with intellectual disabilities. This study employed a quantitative meta-analysis to examine the effectiveness of structured workplace support interventions in increasing long-term employment retention among adults with intellectual disabilities. Guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020), relevant studies published between 2020 and 2026 were systematically identified from major academic databases, including Scopus, PubMed, PsycINFO, ERIC, Web of Science, CINAHL, and Google Scholar. Studies were included if they investigated workplace support interventions for adults with intellectual disabilities and reported measurable employment outcomes suitable for quantitative synthesis. Effect sizes were standardized into correlation coefficients (r), transformed using Fisher's z transformation, and synthesized using a random-effects meta-analysis model to account for methodological and contextual heterogeneity. The findings demonstrate that workplace support interventions exert a statistically significant and practically meaningful positive effect on long-term employment retention among adults with intellectual disabilities. Supported employment programs incorporating individualized job coaching, workplace accommodations, employer engagement, and person-centered career planning consistently produced stronger employment retention outcomes than conventional vocational placement services or unsupported job-seeking approaches. Moderator analyses further suggest that intervention intensity, employer involvement, organizational inclusion practices, and individualized workplace supports substantially influence employment sustainability. Moreover, interventions emphasizing continuous post-placement support, self-determination, and collaborative employer–employee relationships produced the most favorable outcomes across diverse employment settings. The study concludes that workplace support interventions represent a critical mechanism for promoting sustainable employment among adults with intellectual disabilities. Beyond improving employment retention, these interventions contribute to increased job satisfaction, enhanced workplace participation, greater economic independence, and stronger social inclusion. The findings support expanding evidence-based supported employment policies, strengthening employer engagement, improving vocational rehabilitation services, and promoting inclusive workplace practices as essential components of disability employment policy.